I'm from HK and in my mid 50s. There're indeed many mysteries surrounding Lee's death. Lee and Chow's relationship was deteriorating towards the end of Lee's life but not to the extend of killing Lee. Why kill a goose which could lay golden eggs? Chow was a shrewd businessman but not a triad society leader.
Lee never punched Chow in the office. It was strictly rumor. The Western readers may have been misled by some people or articles. Remember Lee once threatened Lo Wei with his belt knife but not his fist. He would kill the old man. Similarly, Lee never resort to using his fist against Chow. Yes, they might had heated arguments but Chow always gave way and knew how to calm Lee down. HK reporters once said only Linda and Chow were able to let Lee cool down because they understood his character and hot temper. Chow was well-known for his good EQ.
Also, Chow never reported in the press his relationship with Lee was like dealing with a mindless spoiled child. Oh man, that was an article written by a GH senior editor in one of the GH magazine. Lee was furious and said some threatening words towards this man in front of Chow. It was again Chow who cooled Lee down and didn't blow the matter away.
After so many years, people have been mixing up facts with myths.