He would still be a formidable opponent, because his offence is so potent, but I think he was becoming easier to hit and his punch resistance was declining. He had the biggest heart so he was able to pull out those Golota fights and he probably would have been able to pull out more fights. Golota was a very very good fighter at that time. Bowe was still a serious problem for anyone.
The sad fact was that Bowe was never that good to begin with. The meshing of styles between he and Holy created exciting fights but it was more a Gatti-Ward chemistry than true greatness. He wasn't durable, had a porous defense especially inside, willingly discarded his physical advantages to fight a small man's fight. He was there for the picking but deftly avoided many of the harder hitting opponents. That a B-rater like Golota took him down was only fitting.