He fought GGG, Errol Spence jr, Porter, and Crawford and was never knocked out cold. He was stopped by GGG who hits harder than Canelo because he broke his orbital, same against Spence because of before mentioned injury. He quit against Crawford because I suspect he realised he no longer has it.
Could he have done more? Absolutely but I suspect it had something to do with others seeing him as a high risk low reward kind of fight. I reckon that’s what Kahn realised too.
Also worth bearing in mind the JoJo Dan fightwas ordered as a mandatory so non avoidable.
Brook was also attacked with a machete which took time away from his career and he suffered 2 orbital bone fractures. I disagree with the Spence fight he was winning that before the injury, Dom Ingle claimed it happened a round or 2 before the stoppage. I dare say, should a woulda, that he would have won that fight without the injury. Brook has no one to blame but himself though as does Kahn for being the reason this fight never happened.
General consensus was Kahn could outbox anybody inc Brook, but Brook could equally time Kahn and knock him out.