“Very few people have their own water wells anymore.”
That depends on the state, in MI lots have a well.
You can drive a pipe in the ground most anywhere here and get water. All you need is a ‘well point’, pipe, and a maul, all available at the local hardware.
In some places in MI clean fresh water boils right out of the ground, you can connect that to your house with no need for a pump.
One of my brothers went 25 years with no electric pump on his well, clean fresh water in his house with plenty of water pressure(about 40 PSI). He added a pump when his pressure got a little lower, he still had good water flow.
Clean fresh water, wood heat, and a septic system, most in MI would do just fine.
Rural, possibly, yes.
Suburbia? No way.
Here, fresh water is a 300ft+ well. We priced it and with the cost of drilling it was $10K+ including the capacity to hand pump.
Most incorporated areas have bylaws that prevent individual ownership of wells.
Those people will still need water. And may be on the move to your vicinity to find that. There are probably way more of them than there are of you. In the NE and I-95 corridor, there are millions of such people.
While your particular region may fare OK (I’m not buying it though, you will have to share resources with people who live in the suburbs when they show up at your door and I doubt that will happen), most parts of the country that are involved in manufacturing, tech and medical care will be hellholes after a week. Maybe less than a week.
The loss of people with specialized knowledge (surgeons, computer specialists, researchers, etc) would be difficult to recover from. You can’t just manufacture those people in a 2w program, they represent a decade or more of post high school training. Those are the people who live in the urban jungle and its associated suburbs. And regardless of your opinion of ‘blue states’ and ‘blue cities’, it would be difficult to recover the loss of the specialists as a nation.
Ditto the transportation hubs. If the blue cities go up in flames, so does the interstate system, most large river crossings and railway interchanges. Not to mention the ports of LA, Elizabeth NJ, and the rest. If Houston went, you can forget lots of heating fuel in the NE. For the forseeable future. Not to mention the pipelines from the refineries there to the rest of the country.
So you may have potable water, but loss of the millions of people without it would affect you regardless.