There are a lot of potential monster players that suddenly quit the game for whatever reason, I think those are usually the smart ones who realize it's not a good way to make a living. I knew a young man in NYC in the mid 90's who improved his game at a truly frightening rate. He went from a C player to an A+ player in about a year and half, he was practicing like a demon every chance he got, his high run in straight pool was 57 at one point and then 3 months later I saw him run a 91 followed by a 67. he started cashing in a couple of Joss events, he was absorbing knowledge like a sponge and everyone assumed he would be a pro in no time, he just had a very, very optimistic attitude about the game. Then he completely disappeared. I ran into him on the street and he said he hadn't picked up a cue in 5 months. He said he realized there was no future in pool and he could make a better living by simply working a regular job.
I think that happens to a lot of people. But to this day I've never seen anyone improve as quickly as that guy.
