We are not powerless in this scenario. The club needs to go to Raiola and say "We want £75m for him. You are his agent and have been drumming up interest, so make it happen."
If we get an offer in line with our demands then great, ship him off.
If we dont get a reasonable offer however, we have various options. My option is to send him home on gardening leave, and leave him there for the next 18 months until his contract runs out. He and his agent need to be made an example of. We need to show the world that Manchester United will not be messed about and screwed over by greedy players or cretinous agents. It is a reputational thing.
From Pogba's point of view, what does he probably want more than anything? To play for France in the 2022 World Cup. If we let him rot at home (not even in the reserves) for 18 months, it massively jeopardizes his chances of being picked for France - especially with the talent they have coming through. Pogba will be 29 when the WC comes around, and so it is probably his last chance to play for France at his top level.
Lets be clear - we wouldnt be doing this out of spite, we would be doing it because frankly he is a bad influence around the club and a disruptive member of the dressing room. We would also be doing it to make a statement that greedy agents and disruptive players will not be tolerated. Maybe if he sacks his agent and signs a new contract (probably with a slight pay cut) then he can be given another chance, but his ego definitely needs to be checked right now.
It may cost us a few quid, but what are the alternatives? That we accept a lowball offer? Hell no. Not only does that hand the victory to Pogba/Raiola, but it sets an incredibly dangerous precedent and shows the club to be weak. We will just continue to be taken advantage of this way until we draw a line and say "No."
Again - the club holds power here. Letting Pogba rot at home would send a very powerful statement and frankly, pretty much the entire footballing world right now appears to have come out on our side. I havent seen anyone giving much sympathy to Poor Paul Pogba. If Pogba and his loud mouthed agent are so desperate for him to get a move in January, then they can sort out a reasonable fee for us and everyone is happy. Otherwise, make an example out of them.