Two fold IMO - one there are the people/critics who wanted him to flop/put out stupid narratives about everything he does. Prime example was Focus with Margot Robbie, that was a good movie, but the narrative is it flopped/he can't float a movie, etc. It made $160M on a $50M budget, the shyt is a heist movie, it's not supposed to be a blockbuster, it's like they want everything he does to suck.
That said, breh did stifle his own career IMO. His over reliance on sci-fi, sequels, and reluctance to play controversial/artsy roles kept him from being able to widely garner the acclaim his acting skills were/are capable of. He needed/needs more breadth. Pair that with the times he did think he was taking more unique roles, he chose really bad movies. His role selection sucks. I honestly think playing Django or doing something like Denzel did by playing the polar opposite of what people expect from him would have reinvigorated his career.
I think he's still capable, he just needs better guidance for film selection.