The difference in costs for everything else is similar or worse in rural areas though. For instance, a 32" TV costs the same on Amazon no matter where you live, but when the water company only has 900 customers instead of a few hundred thousand the cost-per-gallon sky rockets.

As a counterpoint, there are some places (like this one) where more water than you can want just falls from the sky.

The water here is cheap no matter how many people are connected. If it weren't, you'd just dig a modest hole in the ground and suck out what you need.

Plus with progressive tax rates and high taxes in CA that ratio realistically goes more towards 1:6 or higher

But is $40k on offer in these more affordable parts?

South Carolina is not large. If you were willing to commute for an hour, if you lived in the center you could work almost anywhere in the state.

A one hour commute could easily cost ~ 5k/yr in fuel alone (50 weeks * 5 days * $3/gal fuel * (60miles / 20mpg)), instantly cutting that increase from 30k to 40k in half.