Ragequit
Rock Star
Silver Level
Many of the players you mention consistently run deep in tough large field tournaments and consistently cash in them. Regardless of whether they've been sponsored or not they are still achieving a very difficult task. Some have gone into the Poker Hall of Fame. Not for their ability to get sponsorship, or raise buyins, but because they simply outclass the majority of their opponents and use pure intelligence to defeat them. The people you have described also built their poker bankrolls and careers during the time when Poker was still very unpublicised. They faced much softer competition than today's pros have to contend with. But i still acknowledge that it wasnt an easy task. Their bb/100s and ROI% were likely much higher before Poker exploded. This is because the market is now flooded with whizz kids and math sickos who weren't there in the same numbers during the 70s-90s... and none of the analysis tools and software existed back then.. so you were either a genius with the math or you weren't. Now everybody is becoming a stats guru and collecting millions of hands on opponents. This wasnt possible before, and so bankroll building is far more difficult as your tendencies are already known before the hand begins. It's not surprising that many players you describe are now having to look to stakers and sponsors. Their win rates can't generate the same amount of buyins as they did in the past.
They need some guys to play against at the players and bragging to your friends that you outplayed them. Pokerstars and every poker room is a company and this is a way of promoting its product.