I think there is much to recommend this. Sadly, most of that is people's sense of identity, a generator of all manner of irrationality. But we work with what we have, I suppose.

Edward Longshanks took (rather forceful) exception to Scots secession. Abraham Lincoln took (even more forceful - why was the Anaconda Plan abandoned, anyway?) exception to Southern secession. I know Texas secessionists ( glancingly, not well ) and I tend to quote Sam Houston to them. They're not to be taken seriously. Yet.

I see no reason to think the pattern would abate. Brexit isn't in that set because the Eurozone is barely even a convenient fiction. It's a con job, the sort it would take an H.L. Mencken to characterize properly.

I can't even choose a pet narrative of how it is we should be organized in that way. I just know how it is - we're in really big chunks. I credit the sort of peace we now enjoy somewhat to the size of those chunks.