Speaking for myself, part of the reason I don't mind a little disparity is simply due to the economics of things. The larger markets already subsidize the smaller markets, not just in financial terms, but in bringing eyeballs to ballparks and TVs. (Without doing any research on the topic), I would guess that the vast majority of baseball fans ONLY pay attention to their own team, unlike in the NFL or NBA. I know that once the Brewers are eliminated, my interest in baseball really craters. If MLB wanted NFL-levels of parity, MLB would lose millions and millions of eyeballs (and dollars) because if the Mets and Yankees were as bad as the Jets and the NY Football Giants, it would ultimately impact stadium revenue AND TV revenue in that market.
If we were being honest with ourselves about desiring a perfect competitiveness-to-revenue ratio across the league, The Brewers would move to New York to become more financially AND competitively viable.
With this said, I believe MLB is nearing that tipping point of competitiveness, and that further rules will need to be added to maintain the current competitiveness of the league.