Still, if you are actually committed to being a "pro pool player" than you need to compete in the top events. Sponsorship and success only come with playing in the top events, honing your game against the best, and winning major titles and getting international recognition.
Bergman has had some big wins that paid well, he had a place on the MC last year and got some money from that, and he will likely be there this year as well. A pro pool player has to take winnings and earning and start to reinvest them into things like the World Championships.
If a player Bergman's caliber has decided not to bother with world championships and the major international events throughout his career they might as well quit pool and go get a job because there is really nowhere to go in this sport without playing at that elite level. He has done anything he will ever do in this sport at this point, and without stepping up to the next level there is no point in staying where he is.