That's true in the US and Asia, but not in Europe, where you will find that the majority of three star-rated places aren't in big cities to begin with.
The original idea (~100 years ago!) was to boost demand for cars and tires in general, and what better way to do that than to provide a list of amazing places you'll only get to visit as a motorized person.
> There once was a time when people had to be convinced that a car was useful. That was the situation in 1895, when brothers Edouard and Andre Michelin developed a new design for a car tire...
> First published in 1900, the guide’s 399 pages contained all the information drivers needed to “go touring” through French towns and cities. Only restaurants attached to hotels were included, and they were listed rather than carefully rated.
1. http://priceonomics.com/why-does-a-tire-company-publish-the-...
When you have the requisite density of Michelin reviewers, you can be in the arse-end of nowhere and still get your stars if your food, service and venue are up to scratch.
And to the person who downvoted me: just so you know, I rarely care about this, but if you downvote on a wild guess, you need to double check your interpretation of "wild guess."