I think this will drag out into the summer, but not into next season. In the end, DDG will sign. Madrid was the only club I considered a threat to take him. I don't think he wants to sign for PSG, play in a laughable league, and fade out of the spotlight. I don't agree with the "give him whatever he wants" crowd, but I also recognize that the club has screwed the wage structure with the Sanchez signing.
So although I find this entire saga annoying, I cannot really blame DDG or his agent for taking advantage of the situation that quite frankly, United made for themselves.
Assuming Pogba continues to play well and improve even more, I cannot even imagine what his negotiation is going to look like.