Not trying to take sides in this, as I feel that both sides have strong arguments. Are there fewer pool players as a result of video games? Absolutely. Should professional gamers be recognized for their skill and perseverance? Absolutely. That pretty much sums up my feelings on the subject.
I'm also not sure what the exact criteria are to be considered a "professional gamer", but there have been gaming organizations and competitions ever since the first arcade games
(Asteroids, Defender, Pac-Man, Donkey Kong, etc.) became popular in the late 70's and early 80's. Anyone interested in seeing how professional gaming got its start, as well as learning a bit about some of the pioneers of competitive gaming, should watch a very good documentary called "The King of Kong - A Fistful of Quarters". A trailer for it can be found here.
http://www.youtube.com/watch?v=xMJZ-_bJKdI
Good rolls,
Aaron