Per wiki policy, Spoilers Off applies here and all spoilers are unmarked. You Have Been Warned.
The Giftias are designed to last only 9 years to improve the SAI Corporation's profits.
As a company basing its business on selling androids and other robotics, the SAI Corporation would likely want their customers to continually purchase a newer Giftia. While this could allow a family to have an up-to-date android, it would also give the corporation an opportunity to make a considerable profit. With those two ideas in mind, it wouldn't be surprising the predetermined lifespan was created on purpose rather than being a result of technical difficulties as we initially believe. Alternatively...- Sounds like a case of planned obsolescence.
One has to wonder what they do with those Giftia they bring back...- If the company's only concern is making money, then the retrieved Giftia bodies might be reused with a newer OS. Recycling the android body is much cheaper than creating another. Considering how indistinguishably human the Giftia's are already, the only thing that might need updates is the OS.
- Alternatively, the limited lifespan thing wasn't planned from the start, but they didn't try/want to fix it later, for some reasons... And ended up passing it up using Planned Obsolescence as a cover up.
The Giftias' predetermined lifespan doesn't exist.
The Giftia can already develop their own emotions and thoughts, so the company might see the androids as a threat to humanity if even one Giftia knows too much of the world or develops thoughts different from the status quo. Of course, the profit-obsessed reasons for the above WMG can also apply to this as well. Regardless, it would be a rather striking twist in the tale that could bring serious shockwaves to the characters.- Jossed, Michiru's Giftia foster father became a Wanderer after his lifespan expired, the consequences of which are shown in Episode 5.
A Giftia can be jailbroken.
With the sheer amount of potential these androids have, it wouldn't be a surprise if some clever hackers saw them as an opportunity for quasilegal upgrades and improvements. From newer artificial souls to extend their personalities' lives to military-grade augmentations, the possibilities for such developers could very well be endless. The Reveal will eventually happen.
All the other entries on this WMG are about what The Reveal will actually be when it does happen. Isla escaped her deactivation.
Isla hacked the company's servers to extend her life time, explaining her memory failures in the first episode and her complete dread at doing her task.- Jossed, even if she did fool everyone into believing her lifespan had more time then she did, she would still become a Wanderer and go berserk as seen with other Wanderers in Episode 5.
Soylent Green is people
People is a key ingredient in bot production and this is also somehow related to the lifespan. Related to the above, Giftias aren't even androids to begin with.
Now hold on, given that SAI Corporation is clearly a company focused on robotics, why would any troper state that? Well, think about it for a second. We've seen them express a high level of intelligence and a wide variety of emotions and they can eat and drink (as implied at the end of the pilot episode). More damningly, however, Isla was also seen bleeding, gasping for oxygen when she surfaced from the water, and training to maintain her strength. These functions imply that Isla is made of organic tissue and muscle rather than mechanics, leading to two possibilities: 1. Giftias are Human All Along or 2. Giftias are original biological beings that are highly modified to be compatible with SAI's architecture. Why is Kazuki so protective of Isla? It's because she's actually past her designated lifespan.
It is more likely that Isla is simply near the end of her life. However, if anyone would know of how much time the terminal service department's Giftias have left in their respective lives, it would probably be Kazuki. This theory would explain Kazuki's reluctance to let Isla back into the field, as any shenanigans from Isla's end could draw attention from her superiors and the trouble she would likely face if she kept Isla past her shelf-life. It would also explain Isla's quirks such as refusing to press doorbells or clumsily jumping off apartments, especially when you remember that she was the one who retrieved the most Giftia in her department.- Jossed: Isla has about 2000 hours(about 83 days) left. Moreover, as Episode 5 illustrates with Michiru's adoptive father and Marcia, Giftias like Isla will end up as Wanderers if they exceeded their lifespans.
Wanderers could be used for military purposes.
With Giftias being gifted with super speed and super strength, they would be the perfect soliders for PMCs and military. Thus, when the SAI Corporation terminates and picks up the Giftias near the end of their lives, they could be reconfigured to remove their limitations and converted into combatants once they lose all of their memories and personalities. Of course, there's the issue of them going berserk...- That doesn't seem very practical. Making a military-oriented Giftia from scratch would make more sense. A berserk Giftia does not recognize friend from foe so at best they could be used as one-time-use shock weapons. Making a Giftia geared for war capable of tactical thinking and cooperation with other soldiers would be far more efficient.
- This works on the premise that military Giftia were legal. Think about it. Even now, today, there's questions in the international community about drone strikes and UCA Vs becoming increasingly common. How do you think the United Nations, which currently has a ban on combat-oriented mission PM Cs (see the whole Executive Outcomes fallout), are going to react to super-human powered practically indistinguishable human androids? Calls for bans would be instantaneous. And, from the series, it looks like it is some sort of brick wall. If military/combat Giftia were a thing, companies like SAI wouldn't give two hoots about consumer/civilian sales (much like the rest of the defense industry). Yet... If combat Giftia were not legal... Would you put it past a company to not look for loopholes? Say, take a Wanderer that you were going to scrap/rebuild anyways due to memory corruption and reconfigure it a tad. If said Wanderer unit got dropped off at, say, some opposition/terrorist group's front door and then went berserk... Well... I think SAI would chalk that up as a "happy/coincidental accident." Along with whatever government deals and private funding that just so happened to arrive shortly thereafter.
Plastic Memories is about emotions, not ideas
The plot of the show will end up being about Tsukasa helping Isla come to terms with ending Giftia's lives, including her own impending death. He will end up making her happy, and the final scene will be of him putting a ring on her finger as she is shut down (i.e. Widowed at the Wedding) Tsukasa has a terminal illness
Tsukasa fainted on his first date with Isla, and later revealed that this is a common occurrence. He may or may not be aware of his condition. He and Isla will die together.- Jossed, Tsukasa is not terminally ill and Isla is retrieved in the final episode.
Becoming a Wanderer is part of the planned obsolescence
The SAI corporation has coded "Becoming a Walker" into the androids, because planned obsolescence is easier to enforce if everyone knows that keeping an android too long is dangerous. It's for your own safety that you get a new android, after all. Evidence of a software patch that stops Giftias from becoming wanderers will show up near the end of the series. Eru will discover a way for Giftia to retain their personality and memories when they get recycled.
She'll do this to try to prevent Isla from turning into another "Andie/Olivia" scenario, where her body is reused, but she has an entirely new personality and no memories of her past life. But in a twist of fate, this happens after Isla has already been recycled or shot with the virus to deactivate her.