I don't think it's the south holding America back as much as the common American ethos that is endemic to the entire country. The south has some of the worst poverty, inequality, disenfranchisement in the country. However, all those problems are intrinsically linked to the wealthy costal elite shareholders who designed that regional suffering. They hope we waste time bickering with each other, because it distracts us from every reigning in the people who can freely move their wealth whatever they please. That have no strong attachments to any location, as the ability to freely move capital at their convenience is their biggest strength.

A breakup of America would require a lot more degradation of federal authority to be successful. Neofeudal "liberals" might use the Trump's embarrassment of America as a way to market blue states taking more power from the fed. Only if they manage to disentangle the military and make it more regional can America properly Balkanize. Even a weak federal government will fight to keep America together, as it would instantly lose countless advantages if it allows a single state to leave.

The West Coast in the best position to become self reliant, with everywhere else either being too reliant on the federal government, too difficult to defend if they declared independence, or have a lot to gain by gaining control of the federal government. Texas would be next in line to seek independence, but with the West gone, they'd be better off working with the South to gain control of the fed and dominate the North. The Northwest is vulnerable to pressure from both the North and the South, and the North would have an uphill battle fighting a Southern controlled federal government. The Southern states or Texas might secede if the North ever gained control, but that would only happen if they lost control of the fed after failing to recapture the West.

The biggest thing to recognize about America as a nation-state is that the federal government has such an overwhelming advantage by virtue of controlling specific areas that aren't as productive on their own. Hawaii and Alaska are reliant on the rest of the country by virtue of their isolation, and while an independent West might be able to win the hearts of Hawaii, it's unlikely to win over Alaska based on its current politics. Alaska is an extremely powerful location for the military and would be a huge problem for any secessionist Westerners. Key military production is totally reliant on east coast manufacturing, while the productivity enabled by the Mississippi River makes it a force to be reckoned with. The only way the West could ever stand a chance is if the fed moves a lot more military manufacturing across the country, they are somehow convinced to effectively decentralize/weaken the military, AND some outside empire helps out in significant ways. It's theoretically possible, but it would take a long time and a lot of specific outcomes to happen.

All this is to say that I'm not betting on civil war before a lot of terrible shit goes down. By the time civil war shows up, it might look more like yet another horrifying calamity than a path to a better future.