This sounds bit US centric - not many culture-nations are divided into subnations.States could rise to split and become their own countries. I'm totally for those being cultures, at least with the few that had that potential. California, Texas, for example. Some here say that Texas let the US become part of them. It would not be surprising if they did succeed(sp?) some day - and the Russians have been social media botting efforts to get California to break off even recently - economically it could potentially play its own Brexit scenario at some point. But more importantly for these two, they are very culturally distinct and have a very unique cultural identity that if fostered could be a perfect example of how a culture can rise and grow and become a nation of its own.
If you would like to split Europe like that culturewise, then you would get something like that
Spoiler :