As even a quick glimpse into the Headscratchers page would note, for all the claims of the Party's omnipotence and hyper-efficiency, it's arguable that the very fact that Oceanian society is clearly falling apart in several fundamental ways means that even if the Party is omnipotent and hyper-efficient, realistically it wouldn't be able to remain so for very long no matter how much the Party boasts that it will last forever. Keep in mind, however, that our primary viewpoint character is a somewhat credulous and weak-willed man who has been subjected to bombastic, self-aggrandising state propaganda about how powerful and omnipotent and untouchable the Party and Big Brother is almost his entire life — whether it's true or not, he's going to believe it almost despite himself, even if he doesn't want to.
Goldstein's comment about how all revolutions involve the Middle Class manipulating the Lower Class against the Upper only for them to be supplanted is a very effective observation of totalitiarianism, but it's also the truth for 2 party democracy. One party is in government while the opposition gains the trust of the populace so they can replace the government, only to become much the same type of government themselves. It's our healthy way of dealing with this psychological need.
It's only an hypotesis, but: remember at the end, when Winston contemplates the ongoing war with Eurasia? Namely, if part of the Oceanian forces could ambush the Eurasian armies from behind? And then exactly that is announced?. Well, then Winston declares he "loves Big Brother" because he doesn't even need to doublethink anymore; he sees the world the way he is "supposed" to, with an eternal and invincible Party.
The name "Winston Smith." "Winston" would immediately call to mind the name of Winston Churchill, one of the heroes of World War 2, to the reader when it was first published. "Smith" is a surname for the generic everyman. Orwell deliberately chose this character's name to demonstrate how powerful and how total the Party's control of this world is.
Fridge horror abounds when you read back the passages that Winston reads from Theory and Practices of Oligarchical Collectivism with the knowledge that O'Brien collaborated with other Party intellectuals in writing it; whilst it mostly dispenses with the Party lies and doublethink and tells the truth about the perpetual war, there is nothing in it that actually CRITICISES the Party at all.
Try as you might, you can't find a way for the side of "Truth" to defeat The Party in 1984.
Think about the very concept of The Party itself. It is an all-seeing, all-knowing, incomprehensible entity that can essentially bend the reality of those it controls. Any naysayers or free thinkers? It WILL find them, it WILL rape their very souls and WILL bend them to its will. It likely will never die, and could likely claim that it had been around since the dawn of eternity. Sounds more like an Eldritch Abomination than a government.
Humanity creates its own 'cosmic horror'. The punchline to 1984 is that Humans Are Cthulhu.
If memory serves, though, didn't they specifically say that the system only works if the three Parties are always in constant war with one another? Isn't the end of the book elating for the main character because his Party has finally won the war? What happens when a government like this one collapses in on itself?
The implication there would seem to be that the 'significant advances' are just more B.S propaganda — throughout the book the news broadcasts are constantly trumpeting significant announcements of a similar nature.
Sure you can- time is working against the Party. Much as they like to think themselves omnipotent, they are quite mortal, and the laws of physics are not on their side. If nothing else, they'll eventually collapse under their own weight, because they show a complete and utter disregard for reality, so they'll deplete their resources, destroy their capacity to replace those resources, and then delude themselves into believing everything is fine because they declare that everything is fine. Meanwhile, the entire system collapses.
The limited timespan of the Party becomes even more emphatic when you factor in the intention behind Newspeak: crippling the thought-power of the future generations through desctruction of the possibilities of creating thoughts against the Party or about thoughts against the Party. Without any known countermeasures, the future Inner Party won't have any idea on how to uphold the Party and Oceania. If Eurasia and/or Eastasia avoid the pitfall in their similar governing bodies, Oceania will be ripe for the taking.
Fridge Brilliance is the implication that Oceania's push through Africa at the end of the book might have been caused by a similar decay already happening in Eurasia. (But don't forget that just moments before, Winston was worrying about how the Eurasians' progress there was seemingly the first serious threat to the Oceanian heartland...)
Of course, the Fridge Horror kicks back in when you realize that when The Party does fall, it's going to take a good chunk of human (or at least Oceanian) society with it, and people have been so long indoctrinated with Party propaganda and no evidence of anything contradicting it that whatever takes its place might not honestly be any better.
Well then, there are natural forces, which Orwell was said to haven't explored at all in his novel. Sure the Party could handle some forces like earthquakes and hurricanes. But it takes something too much for them to handle (I.e. pandemics, changes in the Earth magnetic field, climate change) that could bring it down and probably hit the Reset Button on mankind, send them back to the Stone Age.
Quite a big horror moment comes when you realise that Orwell created the world of Oceania by extrapolating the real world rise of Nazism and Stalinism. This rooting in the real world is absolutely terrifying.
An even worse Fridge Logic moment comes when you consider North Korea when compared to Oceania: In Oceania, 80% of the (fictional) population are free, if not politically, then at least to laugh, love, drink, have sex, be merry and maybe, just maybe, even overthrow the Party. The real citizens of North Koreadon't even have that.
Even if you're in the Inner Party, you're leading a shallow life of self-gratification at the expense of others, with nothing to show for it because as soon as you die, you will be written out of history so that your successors can be the ones who made your accomplishments and have always been around until the same thing happens to them. If doublethink were a beverage, you'd be downing it faster than your liquor.
Even if the reader can console themselves with the implication, real or imagined, that Oceania will eventually one day fall and the reign of Big Brother cannot last, the novel is still brimming with Fridge Horror — the horror of Ingsoc might end one day, but that's cold consolation for Winston Smith and the millions more like him who are broken, defeated and ultimately destroyed by it on a daily basis until it does. And even if it does collapse, the way it collapses — and what's left after it does — is most likely not going to be very pleasant...
There are subtle hints throughout the book that O'Brien wasn't just monitoring Smith, but that he actively set Winston up to commit Party treason just so that O'Brien could catch him and break him, seemingly just for his own amusement. Gets even more chilling when you consider the "How does one man prove his power over another?" dialogue they have in the Ministry of Love.
Mind you, it's not for amusement. The Party needs enemies of the people so that it can uphold the perpetual crusade against traitors and goldsteinists. So what should it do after there are no enemies left as a result of the Purges? But of course, create new ones!
At the end when Winston's last encounter with Julia is described, the narration mentions her having a scar across her forehead and temple. This, combined with the seemingly-devoid-of-emotion-and-rebellion mindset, implies the Party found despite Room 101, Julia needed further brainwashing. Thus, she had her prefrontal cortex removed in a lobotomy.
One particularly famous example: Oceania is dominated by the Americas, with the British Isles being little more than a convenient Airstrip One for attacking Eurasia. So why would the Oceanians base their whole society on "Ingsoc" - English Socialism?
This of course leads to all sorts of Wild Mass Guessing about the true extent of Oceania...
Maybe it has a different name in every country of Oceania? "Libertysoc" in the US, "Neomateship" in Australia, "Modern Bolivarianism" in South America, etc.
Or it could be a reference to the Anglosphere (considering that the full implementation of Newspeak will eliminate the concept of Ingsoc—the name itself implies a definition in comparison to something else—we can expect generic references to 'the Party' to prevail over time).
Or perhaps since the author was British, he assumed that Britain had dominated the Americas, not the other way around.
It could even be that Ingsoc is the equivalent of something like the DDR to the USSR. The USSR run the show but the DDR has it's own puppet government. INGSOC could be the puppet government/party of whatever the American party is.