Comparing the two cases of Pogba and Fagioli, I'd still keep Fagioli around for two main reasons. (1) Pogba may not have done it purposefully but it was not the first time he erred and will not be the last. In his case, it's about cheating. Fagioli did not cheat but seem to be part of a collective and stupid game. He should have known better, he is not a kid. But he is not cheating. If he is an addict or not is impossible for me to judge. If the debts are true, it's obviously an addiction. If they are not true, he could be as much of a gambler as many others. If he is an addict, he should be able to overcome it.
(2) Following the last position I took, sporting-wise Pogba is done. He had one cameo since he came where he did look decent but on most occasions he looked more like a grandpa out there. Pogba is not getting any younger and his broken body will only worsen. Fagioli is no kid but has a lot of years ahead of him. He may never become a star player but I still have my hopes he can become a rotational regista.
(3) Yeah, building on that I add the third one, which relates to him being a rotational option. Pogba's wage is a joke. Fagioli is really cheap and given the circumstances, if he turns out decent after all of this, then I expect he will accept a reduced salary.
I have a blind eye for this dude so my bias is very evident. I hope he can recover mentally and, in a year, physically.