Alright I guess Cantona, Scholes and Giggs weren't great players? Or all the players from smaller countries who never got to do anything. Aguero being incredibly mediocre for Argentina. Messi failing to be successful with Argentina. And so on.
There is a debate, and it's one that has been shown time and time again for years and years to prove very little relevance to club level. Sure, if we're talking about a players legacy, it means more to have done it in International football. I'm not disputing that. But as a predictor for actual performances at club level? Means feck all. Genuinely feck all. So many players who showed up in the world cup/euro group stages with a few goals and got overhyped before getting a big transfer and doing nothing. feck, even for Bosnia, Besic got himself a transfer to Everton because Martinez loved him at the world cup only for him to look mediocre as he's a mediocre player whenever he played in the league or even the championship on loan. There are countless examples of why International football is a lower quality setting that is irrelevant as a gauge of player ability and how they'll play for a club, and a completely different world to club football.