I think its fair to say the only person whos career Jon Jones has fucked up more than his own is Daniel Cormier
Its always going to be held against DC that he couldnt beat Jones, but then, we will never know how good Jones was clean (if of course you assume that Cormier is clean which would be putting a lot of faith in him)
You could argue a clean Jones would have lost to Gustaffson
Gustaffson then lost to Cormier
But, we will never know.
Like i say, the only person whos career Jones fucked up more than his own was Daniels