Lack of Land. If there's an area in urban/suburban China the size of a football/baseball court, somebody would've bought it and turned it into real estate.  And unlike soccer, you cannot dribble the ball around street corners to become a superstar.

Football and baseball also require too much sheer strength. Faster and stronger players have too obvious an advantage (just my impression, not sure how true this is). This is against the taste of Chinese culture which prefers outsmarting and out-positioning  your opponents without direct confrontation. While basketball is also a big man's game at pro-level, it incorporates enough skills that an average person can find his way around taller, bigger players.

One last thing maybe that basketball is more individualistic than baseball and football, which fits the taste of the only-child generation to make their own presences.