I think Fedor got this, in my opinion, the only reason Fedor ever lost to Werdum, Henderson and bigfoot is because he changed his style too much. Just like many fighters, you can sit on your achievements and stop performing as you used too, which I think was the case with Fedor, along with other problems like injuries and other things.
Therefore, I don't believe Fedor is necessarily out of it, because he's older now. Some people say that you don't get better as you age, but in this case it's not a problem of aging, it's a problem of not doing what you used to be good at. At the end of his career he was mostly throwing long hooks to try and knock out his opponents and being overly un-cautious, he wasn't as refined as he used to. But that can change, and it's not a problem necessarily related to age.