I don't think changes will be made, at least not so far as to threaten the non-major market clubs.
While collectively, yeah, all the billionaires want to make as much money as they can, and having major-market-only playoffs would create a bigger pool for revenue sharing, more of the billionaires own NON-major market teams. Individually, should these non-major market teams advance, that would be more money for themselves. Even if the incentive for each of these people is solely cold hard cash, it would still be in their best interest to advance as far into the playoffs as they can.
The Pohald's will make more money going to the World Series then they would from their cut of the revenue share should the Yankees get there.