Why do leagues allow perennial losers losers? Why do they not intervene for the sake of the league? Most certainly one could make the case that cellar dwellers such as the Isles and Cleveland Browns and Oakland Athletics are a drag on the rest of the league? I can't think of an NBA equivalent because I don't watch. The Knicks?
Teams are privately owned and can run their teams any way they'd like. The only regulation that exists is that of the salary cap or revenue sharing. The respective owners are the bosses of Gary Bettman, not the other way around. Though, there are no elections, fans can always send ownership a message by not giving them money. As much as it may feel like you do now, you don't want dictatorial governance anywhere in the U.S. But if we had that in sports, theoretically, we'd have a situation like what exists in the KHL where a team is stacked to win. If we had dictatorial governance, all the talent would be funneled to NYC, Boston, Los Angeles, Las Vegas, and possibly San Jose, who would likely become the San Francisco Sharks. So, there really is no availability for league intervention. If there was, things would be worse than most of us can imagine. The only other check that comes into play is any potential owner being approved by the Board Of Governors. Other than that, there has to be something egregious for removal... like John Spano, for instance.