There's an awful lot of ground between "unsafe drinking water" and "megacity".
Take Ault, Colorado, just for instance. Google says the population is 1,947. It declined from 2018 to 2019. (Not sure how Google knows that, when there wasn't a yearly census. Maybe better not to ask - Google's surveillance powers aren't the point here.)
Ault is this little small town. It's on a US highway. It's 17 minutes off of an interstate. It's 27 minutes to Fort Collins, a town of 100,000 people with a state university. It's 1:17 to Denver, a city of 4 million people.
So if you need a hospital, there's one 30 minutes away. If you absolutely need a big city hospital, it's an hour away. That's inconvenient, but you (hopefully) won't need it very often. Need an InstaCare type facility? There's probably one 20 minutes away, and almost certainly one 30 minutes away.
Need an appliance store? It's maybe 25 minutes away. Well, mine is 15 minutes away, and I'm in a big city.
Need a non-remote job? There's a fair amount of tech in Fort Collins. I've had worse commutes. (I didn't like them, but I've had them.)
So I'm not seeing the hard dichotomy between "big city" and "completely out in the sticks". It's a continuum.