What incentive do rural states have to stay in the union if the federal government is controlled by populous state bullies? Wouldn't it be better for them to fragment into separate-but-open-border-countries like the EU?
Probably roughly the same incentives any state has ever had to join and remain in a federation. Things like free trade and movement among states and a combined military. One of the incentives to remain in a federation should not be the ability to disproportionately influence the federal government compared to other member states.