So if we're in agreement that Pogba can be world class in the right system and with the right players around him, why aren't we doing anything to give him the chance to perform at the level we know he can perform at? Why are we persisting with playing him in a system that he's ineffective in? If he's ineffective in this system you either bank on him and mold the team to suit him or you drop him and/or sell him. Ole's doing neither. We haven't been after a defensive midfielder since Ole came here, despite knowing that Pogba flourishes in a system where his main responsibility is in attack (as we saw when Ole took over). So basically Ole's just doing the same thing over and over again and expecting different results.
Deschamps also plays him as part of the 2 in a 4-2-3-1, yes, but saying it's the same role is a massive simplification IMO. Having Kanté around him who can win the ball and lay it off to him for a quick forward pass is vastly different to what he's expected to do here. We don't have a player to win the ball like Kanté does, and by the time we get the ball to Pogba the opponents have already settled. We're way too slow in getting the ball to him, and we're not moving without the ball once we get it in the same way Griezmann and Mbappé do, which leads to Pogba dallying on the ball in deep positions and losing it.
I agree with the last part of your post. We don't really have the perfect midfielders to act as fulcrum to Pogba for various reasons. Matic doesn't have the legs, Fred just hasn't shown enough. We could try a diamond with Fred/Matic, vdB, Bruno and Pogba, but that requires a lot of attacking from our full backs who are, oh wait, shit at attacking (decision on Telles pending). It begs the question as to why we haven't been in the market for one in the four transfer windows since Ole came? I haven't seen enough of Partey to judge whether he's the one for example, but he was available for €50m all summer and we weren't even looking at him apparently.