He showed it... on the pitch? Seriously explain to me how a player staying and not playing means he's better than a player that went to a top 10 team in Europe in a top 3 league and absolutely tore it up for 3 years straight? There's no logic in that. None. Is amad diallo better since Sancho never proved it in the premier league yet ffs?
Pass accuracy... I'd expect City players to have better pass accuracy. Not sure what relevance fewer games played for Foden has. That "take on success" difference is laughably negligible, come on.
Also prove that he's a better passer. Not pass completion percentages. Usefulness. In per 90 stats over the past year, Sancho destroys Foden in xA, key passes, passes into the penalty area, passes into the final third, progressive passes, receives more progressive passes, has more touches in the attacking 3rd, more in the midfield 3rd, more carries into the box, more carries into the final 3rd, more progressive carries, way more dribbles completed per game (with a minor drop in success, not unexpected when Sancho takes on so many more). He has more "shot creating actions" too.
Foden wins in touches in the penalty area (played as a central forward for City vs Sancho playing as a creative winger), he has more xG/90 and takes more shots per game, and is better at pressing/generally defensively where Sancho isn't very good. He's a good young player. But there's literally nothing that suggests he's a better player than Sancho yet, as Sancho has shown world class form for 3 years, since he was 18 and his past 2 seasons have been miles better than Fodens this season. Sancho has been dominating games in the Bundesliga and playing well in the CL for multiple seasons now. Foden had half a year as a starter where he looked good, but still not Sancho level good. And they are the same age.
Like I said. Fine if you think he's a bigger talent, I disagree. Maybe when they were in the youth team at City Foden was better, I genuinely don't know how they were regarded. But Sancho left, like you said got his chance but more importantly than anything, took his chances and has been tearing it up for 3 years and has progressed loads into a genuinely top player and one of the best wingers, or creative players in the world. Foden is 2 years behind Sancho in development, hasn't been close to Sancho on the pitch, so how can he be better if they're the same age right now? You surely can't just disregard actual on the pitch performances in favor of hypothetical talk? That's crazy.
Stop butchering my position with your imagination.