Earlier quoted context omitted.
Why is it a problem to have 300 million people follow the same set of laws, but it's okay to have 38 million people with the same laws? Or maybe California is too big to be a viable state too? Maybe 6 million is the right magic number, and that's why Singapore is still okay? Or maybe 3 million would be better (like Mississippi.)? Then again, the founding fathers knew best (right?) and the largest colony/state at that…
I agree that there's no magic number, but I think we dramatically err on the side of centralization, so cutting it down by an order of magnitude is fine by me. And states do have a general character/culture -- consider the differences between California and Arizona or Nevada. Also, the borders aren't arbitrary: there are governmental structures that have built up and settled over centuries. Really, I think there's no…
IMO this isn't true now, and it's demonstrably been getting less and less true in recent years[1]. The claim that states seem like they have different cultures if you consider it isn't really helpful either: The human brain loves imposing structure on things, so if you claim that a certain area is a single entity, naturally one's tendency is to think of things as "Californian" or "Arizonan", etc. In much the same way, one thinks of an Italian living on the French border as ethnically Italian, and a guy living a few miles away as ethnically French. Drawing arbitrary lines is convenient enough, but pretending there's any sound reason behind these distinctions is silly (look at the recent history of Central/Eastern Europe to see exactly how arbitrary state lines are).
[1] I'm referring specifically to the fact that it's a well-studied phenomenon that the urban/suburban/rural divide in culture+values is becoming a lot more significant than the state-to-state ones.