He would have lost by now, IMO.
Now before I get flamed or people start arguing with me that he's better than all the UFC heavyweights and blah blah blah, I'm not saying he isn't as skilled as the UFC HW's. And keep in mind this is just my opinion.
I know I've never been a supporter or fan of Fedor, but hear me out. We've seen that one of if not the biggest weakness for Fedor is that he cuts pretty easily. That's where his only loss (I know, I know it was an illegal shot but it's not like it was on purpose) came from. But in PRIDE, there are no elbows allowed. In the UFC, elbows are allowed and are used all the time by wrestlers or anyone who decides to throw one on the ground. They're one of the most effective ground strikes, and what messed up Cro Cop in his fight with Gonzaga. Chances are, if Fedor spent as much time in the UFC as he did in PRIDE, he would have taken some elbows from a big strong wrestler. And that could open up a cut leading to a stoppage.
Again, just my opinion, and no disrespect to Fedor even though I don't really like him. I'll admit he's one of the best fighters in MMA (even though I think he'll lose a couple times before retiring unless he retires after his first loss to Arlovski