Good thread, but how does one compare pool to baseball, boxing, football and other sports in which you get paid the same whether you win or lose.
At top pro level, baseball players and boxers don't face the potentially grim possibility that their expenses will exceed their pay and that they will lose money. The economic realities of pool eventually weed out the unworthy, but as pro pool consists chiefly of "show up and play" events in which no qualification criteria pertain, even the greats are able to compete beyond their realistic shelf life.
I remember having very mixed emotions watching the legendary Buddy Hall at Derby City this year. Watching him warm up, it was pretty obvious that he was incapable, or at least nearly so, of making a deep run in the nine ball event. On the one hand, it was great to see one of the all-time greats present, but on the other hand, watching a legend perform so far below his one-time level of sustained excellence is a bit unpleasant. Still, I understand and appreciate that Buddy may compete as long as he chooses to, and that his presence is always something special.
Another disimilarity between pool and sports like baseball, boxing, football, etc. Pool players don't often get concussions or serious, life altering injuries/conditions from competitng. The tears we've wept for the likes of Muhammad Ali and Junior Seau, both of whom paid a huge price for competing for too long.
Guess what I'm saying is that the comparison with other sports doesn't really work. In pool, the economics get in your way soon enough once your skills diminish, but in other sports, they keep paying you.