What else can you based on?
Youth games? How many look like they are world beaters in those and came out as nothing?
Looks it looks like I'm underestimating his ability. I am not. For United's sake, I hope he becomes a world beater.
It is just that people are not managing their expectations with him properly. It got to the point of being ridiculous now.
You can base it on talent. Talent doesn't mean a player has a god given right to become world class or even a decent player in senior football (Ravel is a prime example of this). That's not the point of contention though. It's, does Gomes have the talent to become world class and the answer is yes based on his ability which we saw at youth level.
Gomes is not McTominay, who was if you asked most United youth watchers, pretty average talent amongst United youth players. Gomes is also not Rashford. Rashford was one of the standout talents for his generation of United youth players, along with Gribbin. If you were to compare him to youth footballers across Europe, what he showed at youth level wasn't particularly stand out in nature. And by that I mean that the player is seen as a prodigious talent. He was a good talent, but I feel plenty of those types exist every year. Gomes was the most talented English talent produced by United since Ravel, and prior to that, Scholes? Gomes made his way to the u18 side earlier than Rashford for this reason (also dominated that level at a younger age), and why he also made his United debut at age 16.
It's clear to see why. His technical ability is greater than everyone we've had at United besides Ravel, and possibly Pogba. Others like Januzaj, Gribbin, etc... come close, but I feel like everyone would agree that Gomes was better at least slightly. The vision he showed at a really young age is rare.
I think the fact that Gomes managed to win youth golden balls at tournaments involving the biggest clubs show this. And if you were to ask English youth enthusiasts, they would tell you that Gomes was one of the early standout talents of what is largely seen as a golden generation for England.
Important to note that, after I've said all of this, It's not to hype him up as some guaranteed star. He's clearly not Messi or Rooney. But would I be surprised if he becomes world class if he manages to put his talent to use at the senior level more than I would be for Rashford, Lingard, or McTominay? No.
Thats what people are basing his talent on. It's not through pre season performances. It's through ability. Ability to have the ball stick to his feet. Ability to pick out a final ball. I do feel we're agreeing that Gomes isn't destined to be some world beater. I just feel like you're conflating that with the idea that if it does work out for him, he could be world class. Just like if everything went right for Ravel he could be world class.