He will stay in ManUTD for sure. Real Madrid hasn't enough money for Pogba's transfer. I mean, they must sell because of FFP, but they have so "expensive" players, which no one wants to buy. Juventus can't buy Pogba and can't give them a salary as they have in ManU. At the moment, United does not need to sell them, also they need to have a big star in the club to keep the reputation and satisfied sponsors (just marketing potential). You can remember the last few signings. Di Maria, Falcao, Ibrahimovic, Sanchez, Mourinho etc ...
This is a false statement.
In Italy, we have a new law for workers from other countries, where they need to pay taxes only on 50% of the salary.
For a faster understanding
Pogba now takes 17.071.600,00, if Juventus wants to pay him the same amount he will cost "only" 17+25%(17)= 21.25m with taxes (same as DeLigt 12+25%(12)=16)
Dybala for example now takes 7.5m with the full taxes, that's mean 7.5+7=14.5 with taxes, not os big difference.
Again the problem is to sell other players before trying to take him.