Because Piccolo was doing a shit ton of training that Gero didn't know about; they all were. Gero's calculations and predication were made under the assumption of their normal growth rates and training regimes. They actually explain all of this.
Yeah, if Gero isn't mind-f*ckingly stupid, he accounted for a group of martial artists who spend all day intensively training to spend the next three years intensively training.
The idea that he couldn't accurately predict what those three years would produce because of all the buffs everyone got on Namek makes more sense to me, especially since - as noted - we already know he had no idea what a Super Saiyan was.
Namek was the wrench in Gero's machine, made more potent by how thoroughly he outsmarted himself in his Android designs.
If Namek hadn't happened, the energy absorbers would have been fine. If he hadn't gone for theoretical advantages instead of pragmatic ones, Namek wouldn't have made a difference.
EDIT: I mean, Tien and Yamcha didn't benefit much from Namek, but it's not like they did a whole hell of a lot against Gero anyway. They were mostly there for moral support.
edited 12th Oct '17 7:58:33 AM by TobiasDrake
My Tumblr. Currently side-by-side liveblogging Digimon Adventure, sub vs dub.Plus, I think it's worth noting just how exponential Piccolo's power boost from fusing was. It's what sets up Vegeta's "power levels are bullshit" line that so often gets quoted out of context.
"Back on earth, the Namekian couldn't even stand up to Nappa. And now he's taking on Freeza! In his second form!"
No beer?! But if there's no beer, then there's no beef or beans!It really is. Of all the bullshit power-ups on Namek, Piccolo's was the bullshittiest, beating out even Goku's final Zenkai.
To go from 3,500 to 1,000,000 is a permanent power boost of 286x. Beats the hell out of any Super Saiyan form short of 3.
My Tumblr. Currently side-by-side liveblogging Digimon Adventure, sub vs dub.In Trunks's future, he fought the infinite energy models, not the energy absorbers. They beat the hell out of everyone even in the present. Even Super Saiyans were no match for them. They're just so much better than the energy absorbers.
There is no shame in losing to 17 and 18.
edited 12th Oct '17 8:02:39 AM by TobiasDrake
My Tumblr. Currently side-by-side liveblogging Digimon Adventure, sub vs dub.I didn't say there was.
My point is that Piccolo and the others flat out say they were training much harder than they ever would have been if they didn't know about the androids in advance. You can't discount that when talking about why things went differently than Gero expected.
Like, Piccolo as he was on Namek would not have been able to stand up to either 19 or Gero himself.
edited 12th Oct '17 8:07:48 AM by LSBK
Piccolo went into Namek fairly confident he could take on this Freeza guy everyone's been freaking out about, so he must have gotten stronger while on Kaio's world. Personally, I think Namekian fusion is actually one of the weaker power-ups in the franchise. Piccolo fusing with Kami took him from a bit weaker than the Super Saiyans (Krillin claims that his power is close to theirs) to about even with 17, who was a bit stronger than the Super Saiyans. Metamoran or Potara fusion's probably stronger.
Piccolo was confident sure but so was Vegeta, neither knew what the hell they were getting into.
He was likely about as strong as Vegeta was taking on first form Freeza, maybe a little less so. And the training curve in Z really isn't that high unless people are using 'special methods' so he wouldn't be that much stronger if he didn't get the power up from Nail.
I think we've brought this up before, but was there ever a real reason for why Gero could never get 17 and 18 in line?
I assuming they just hated him due to him kidnapping them off the streets and converting them against their wills (...holy shit, they are basically Kamen Riders!!!), but I've also read that they just had naturally rebellious personalities, and likely would have gone against him even if he'd gotten them to willingly volunteer.
Because in the end, even with all the things he didn't calculate, and how much of a Spanner in the Works both Namek and Trunks warning was (especially the latter since it resulted in an extra three years of intense training), 17 and 18 were still miles ahead of the Z Warriors by pure accident.
One Strip! One Strip!Also do not forget that Trunks era 17 and 18 are actually weaker than the prime timeline ones. Trunks could actually stand on his own 1v1 for a time in his era, it was the 2v1 that got his ass kicked every time, prime androids kicked his ass solo with any effort.
Trunks even brought it up in the show.
Yeah. I always thought the future ones being weaker was just due to them never fighting all out against Trunks, so he never knew how strong they really were.
One Strip! One Strip!I don't actually remember. I recall Saiga or someone bringing it before.
I remember there was a special chapter or something where 17 says that he was holding back like half his power against Gohan, which is why people think Trunks is wrong about present 17 and 18 being stronger.
Still, I always found it weird how people thought that was out of place with everything else going wrong. Plus, Trunks must have known they were toying with him, otherwise why would they keep leaving him alive?
edited 12th Oct '17 10:05:07 AM by LSBK
Gohan's kind of shit at fighting, actually, at least as far as instincts go. Which probably means that Trunks is too. That might hurt my greater point, but, eh.
Gohan has a ton or raw potential, but he's never been shown to be as in tune with things the way Goku and Vegeta are.
edited 12th Oct '17 12:11:02 PM by LSBK

Dr. Gero is a very intelligent stupid person. Or maybe a very stupid intelligent person?
It's definitely one of those two.
edited 12th Oct '17 2:37:44 AM by Hobgoblin