Counties are perfectly capable of being 100% in charge of their own schools, roads, police. They largely are, but subject to a great deal of probably unnecessary state control.
And then it creates a ton of uncertainty. A different thread was already complaining about the uncertainty of whether children can inherit debts from their parents, which varies from state to state. Is it really a boon to have it vary county by county?
"Simpler" would generally be to centralize what can be centralized. Put all your eggs in one basket, and then make sure it's a really good basket. That's not always the best policy, but if you're looking for the simplest policy, it's usually Don't Repeat Yourself.
And I find it equally weird that each separate state gets to define health care regulations, such that separate companies are required in each different state. Lots of duplicated efforts.
There are certainly some functions that are best managed locally, and I suppose there must be some value to the "laboratory of the states" notion (though there are way, way too many variables for any of these experiments to actually be informative).
But in general, yeah, there's a bunch of stuff that I'd just as soon see pushed up rather than down. It would save a lot of headaches. There is surely some stuff that could be pushed down, as well.
I grew up in southern MO. Arkansas was only about a 40 minute drive away, but I can always tell when I'm there compared to at home. The people dress and look a bit different, the houses look different, it's just a different culture. California and New York are like alien worlds to me. The idea that such different people should live under the same framework seems like a good way to amplify regional tensions.