many reasons. 1st, you take that Pogba leaving bullshit out of your ass, Suns style. Marotta said recently he is going nowhere, we are in a CL final, why the hell would we sell our most valuable asset now? that simply makes no sense! also, Raiola doing everything he can to get him to PSG?

thats something Metro would come up with
2nd, PSG hates us for Coman is another bullshit that makes no sense. these things happen all the time, why would they hate us for their own fail. PSG doesent have the upper hand in this. if Cavani wants to leave (which all rumors are indicating right now, doesent mean its 100% true though), then they can do very little, except to sell to the highest bidder. we are among the teams that want Cavani, we can afford him even with buying Dybala and without selling anyone important, so if we meet the asking price, and agree terms with Cavani, he is ours. its as simple as that.
another thing thats quite irritating is the underrating of Juventus by you and some more. "why would PSG sell us Cavani?" you ask and then go on and write 2 walls of posts where you think we will bend over to them the moment they come calling and sell them Pogba for the 1st deal they offer us. well, why would we sell Pogba to them? have you thought about that? yeah thats right, no reason,
just you making up fairy tales to have something to moan about.
one last thing. if you have wondered about why we would sign Cavani if we already have Tevez, Morata, Dybala. as joker said in another thread, it might seem like too much to have 4 strikers of such caliber in the team at the same time right now, but if you know that Tevez will leave us next summer, and Morata can leave too in 2016, that would mean our current starting duo is leaving in the same window, what then? sign 2 new strikers and start over? we are preparing ourselves for that summer already. Dybala and Cavani are great opportunities, this way we are prepared for if one or both Tevez/Morata leave. Dybala might be ready to overtake from Tevez by then, Berardi is also most likely returning, and then there is Coman. if Morata leaves, we would still have a Cavani and 30M to spend on a SS if all 3 of the above mentioned turn out not good enough.
Marotta is doing a brilliant mercato again,
just relax and watch him do his magic once again. also, he wont sell anyone important, stop overreacting