Proof, you mean like a smoking gun? Durant isn't stupid enough to publicly say he left OKC because Russ is a selfish ballhog who cares more about his own stats than winning. But, all the evidence is there and there are plenty of articles that describe the tension between the two. Ultimately, do you think if Durant was happy playing with Westbrook and felt they had ANY chance of winning a championship he would have taken less money to go to GSW?
Here's just one article on the topic. If you want more, just google why did Kevin Durant leave OKC.
Saturday Shows Why Kevin Durant Left Russell Westbrook
Don't like articles and quotes from sources close to the team (no one will ever say anything on record, or they will be fired like Kim Hughes), just go back and look at the game logs and stats for the 4th quarters of playoff games where Westbrook consistently froze out the more efficient scoring Durant. This goes all the way back to their second season together in OKC and continued right up until they blew a 3-1 lead against GSW last year.
Just go back and look at the stats for their 2012 finals series against MIA. In that series, Durant got 104 FGA to Westbrook's 120. Durant shot .548 FG% and .394 3FG%. Westbrook shot .433 FG% and .136 3FG%, yet he constantly called his own number more than Durant's especially in the 4th quarter when Durant would often go several minutes without touching the ball on offense. Durant was always a far more efficient scorer than Westbrook, but with the game on the line, Westbrook consistently resorted to hero ball. The bigger the stage the more Russ craved, make that demanded, the spotlight - always to the detriment of his team.
That's just one example, but it was part of a pattern that was repeated year after year after year until Durant had had enough and left. He was unhappy playing with Russ and knew he could never win a championship with Russ playing hero ball and freezing him out. He was right. I've been saying the same thing for years and also predicted back in 2012 that Durant would eventually get fed up with Westbrook's me first attitude and flee OKC.
But hey, triple doubles, MVP! MVP! MVP, slurp, slurp go the fan boys. Sure, Westbrook is an amazing physical talent that puts up video game like numbers. Too bad there is also a mental aspect to the game that will always hold Westbrook back. He will never trust his teammates when it matters. He will always try to do too much and he will always fail. He'll continue to have gaudy stats (both good and bad - 47.0 USG% and 6.0 TOV/G in that HOU series), but will never win anything. Basketball is still a team sport and Westbrook just isn't a team player.
BNM