Except for Italy, Peru, Mexico, Japan, France, Thailand, and many other countries where you can find top quality food in thousands of small towns and out of the way places. So probably not a great rule to go by.

You can get top-quality Japanese food in thousands of small Japanese towns, and top-quality Thai food in thousands of small Thai towns. However, rest assured you will have a very hard time finding (say) Mexican in either. The only places in either country where you have a genuinely cosmopolitan food scene are Tokyo and Bangkok respectively.

What is top-quality American food, and where do you find it?

Not an American, but the last time I rocked up to a random small American town and chose a random small restaurant, I had a really good turkey chili burger [1]. Hardly gourmet, but delicious, and it's quite difficult to find this kind of thing outside the US.

[1] The "Chili Monster" at the Dillinger in Boulder City, NV, in case you were wondering. https://www.thedillinger.com/ (Not to be confused with Boulder, CO.)

In addition to the burger previously mentioned, off the top of my head as "American cuisine" there's obviously barbecue, as well as Southern cuisine, Cajun/Creole, and -- while some might argue -- I'd throw in Tex-Mex and New Mexican (e.g., the state of New Mexico) as gastronomically distinct. Where you find it is, well, all over. You have to do a little research. :) But you can find really well-regarded restaurants around America for those cuisines, across a wide variety of price points.

France begs to differ. You have spectacularly good restaurants in rural areas all over the county (Michelin star good).

Sure, but you don't get the variety. If you move out to rural France but are used to rotating among eating Mexican, Japanese, Chinese, Spanish, Thai, etc. throughout the month, you might be disappointed with the lack of choices.

You are probably used to this rotation just because you grew up in the US. As someone who has grown up in Italy we don't think about food this way, not even regionally. I.e. don't expect a great risotto in Naples or a decent carbonara in Milan...

This isn't a US thing, it's about cities with cosmopolitan tradition. Italians are the complete opposite of this culture.

I think there is a spectrum, the US being a country of immigrants is on one extreme, Italy having been several different independent states up to 160 years ago and having many different climates and cultures is on the other. While it's true that the Italian approach to cuisine might be overly provincial I think that most of the world is closer to Italy than the US.

Being in rural France, I like trying some new foreign cuisine once in while as much as anybody else, but it wouldn't come to my mind to make it my daily routine.

Going out of your way to not eat local stuff is completely pointless to me. People take quite a lot of pride in having good stuff specific to their area.

In the Bay Area you can get, in the same weekend, excellent Vietnamese, excellent Peruvian, and excellent patisserie.

The ingredients are sourced locally for the most part, and the imports are about as good as they can get, and substitutions are sober.

The Bay Area is three or four times the size my département. It could be a country. I don't even walk more than five minutes to buy all I eat...

It's hard to share scales with Americans.