It just comes down to the math of living in a high cost/high compensation area. Your standard of living is highly dependant on the ratio of high economic productivity earners in your unit.
I know plenty of young engineers who are easily socking away 60 - 70% of their post tax income because they basically need a futon to sleep on and a macbook and don't really have many needs. After 5 years or so, they'll have half a million in the bank free and clear which is hard to do anywhere else in the country.
Now add it a spouse who works in non-profits or is a schoolteacher or any other job that's not tech. Now your expenses have risen 2x but your collective earnings has only risen 1.3x and now you're only saving 20% of your income.
Add in a kid and your expenses go up another 50% and your income rises not a jot and all of a sudden, you're in the hole and heading into debt.
Low cost/low compensation locations completely flip this equation around since there's no huge disparity in earnings and large families are less of a relative strain.
Neither is intrinsically better or worse than the other, they simply suit different lifestyles better.