IMO, all talk of "pure talent" is pointless, talent is real, but talent is just what we call the factors we can't manage to spot and point out.
Talent in Zero's case comes down to three main things which set him apart from the other top players, lifestyle and brains and a clear goal which takes precedence over everything else, namely winning.
His life is all smash as far as I understand, not only does he make a living playing smash, he's away from his family and homeland, so distractions are lessened, allowing him to focus solely on smash. He doesn't just have time to play the game, he has time to learn and think about it a great deal.
Yeah he's wrong about stuff in his youtube videos, but it's clear when you watch them that the dude's got a much better mindset than most all other top players. He is very aware that he's just one guy despite being the best, he's quick to question his own judgements and has no problems changing his opinions to account for new information. And TBPH compared to most other top players Zero says a lot less stupid stuff, while saying a lot more smart stuff, just overall showing that this is a guy who could go toe to toe with the great theorycrafters in a debate, if he put his mind too it.
There's none of that childish entitlement and pointless bitterness which is so common. Zero wants to win and he knows what type of mindset you need to do it. He doesn't mind picking the best characters because there's never shame in doing what it takes to win in a competitive game. He doesn't waste cognitive resources on being irritated at janky stuff or lame play styles to the same degree that many others do. Meanwhile Ally's a beast, but didn't use all the tools available to him out of some combination of stubbornness and laziness or something. Had he been up to date with all the recent patch did for Marth as well as been using lay counter and crescent slash Mr R might've not stood a chance, there were plenty of other examples of top players screwing themselves over like this. Abadango could've taken Zero had he been using rose fart, no doubt for one. Not saying he would've, but it would've been much much closer, guaranteed.
Now Zero didn't need to make these adjustments cause he's smart. The mains he has chosen complement each other perfectly, are both top tiers (if you think Diddy is not top you're wrong, sorry) and can both be played in diverse ways.
Basically he rocks a hell of a lot of different play styles and covers more or less all match ups with just two characters. Now I'm not just talking about EVO, he did only use Diddy once. But that Diddy was always there had he ever been in trouble with his Shiek.As it is now, Zero has mastered playing Shiek and Diddy both offensively and defensively, to defeat him you kinda need to defeat 4 characters in effect, beat one and out comes the other.
The human mind can only handle so much and Zero capitalizes on this perfectly. He uses only two characters, allowing him to be a master of both unlike people who use more than two (Abadango's Rosa while very strong was obviously not on par with his Pac and Wario for instance), and they can both be played efficiently offensively as well as defensively. What happened when Mr R was beating a somewhat defensive Diddy? Zero went offensive, easy for him but requiring instant adaption from his opponent. What has happened whenever he's been in trouble in the past? He's switched play style or character and gone on to win anyway. His opponents simply cannot figure all of his arsenal out in the course of a single set.
As far as I'm concerned that's what the raw talent really is.