It would seem to me that no one can feed their family on tournament winnings alone. But tournament success coupled with endorsement money, exhibition money, lessons and perhaps even a book or video might sustain a player.
I know several players who have been careful with their winnings and have done well for themselves, but I believe they are the exceptions.
As for the best tournament, the question is truly a subjective one. The Derby had the advantage of being held inside the host hotel and on a 24/7 basis. One could stagger downstairs at 3am and catch world class action. It is also a rare opportunity to watch top level bank pool and one pocket.
I prefer the US Open 9-ball event. There is tension in the air and as a tournament, I have enjoyed it more. The action at Qmasters is great too. I have seen great hustles go down and titan players match up for days at a time.
Both tournaments draw many people who like watching pool, myself among them. Both tournaments afford close access to the players, but when the Derby is over, everybody vanishes with their winnings...at the US Open, Barry throws a party for all to celibrate the new champion.