I agree with you that "states' rights" need to be ripped to shreds, but why is that, if the states have no cultures? They should just be a microcosm of the collective then. Even in 21st century and i suspect, until travel is dirt cheap and instant, people are not so mobile as you think. The poor kid from south boston isn't going out of state for college, unless he somehow lands scholarships. He's not leaving the state for work in texas, as he can't afford to make interviews all over the place and has no skill set that would lead these companies to offer an interview. What you describe sounds more like upper middle class
The states do have culture, especially where the poor abound, which is why mississippi is so damn bigoted still, but MA has had say gay marriage for a decade. For me, it's that i don't respect their culture of oppression at all, which is why i want to just get rid of states altogether and let the federal courts run things. They basically do already, but this would expedite the process, so that unconstitutional laws aren't constantly passed and stay in effect for years before being struck down