Masters of Doom does a good job detailing his logic in refusing to leave north Texas. Cheap cost-of-living and warm climate were his original reasons IIRC. Even though he could live wherever he wants, he's still extremely practical.
If you're someone like John Carmack, I imagine being able to get, say twice as far with your rocket project due to low taxes and cost of living is rather valuable to you.
If he spent $8 million on that in SF, I don't think he would have gotten nearly as far.
IIRC Carmack said he had to stop working on Armadillo because his wife was concerned about how much it was costing the family. Presumably they were down to their last x million dollars.
They are billionaires because they care about the cost of living. Make no mistakes journey to riches is through the path of making tiny little sacrifices everyday.
Heck, you can make decent money and retire in your 30's if you are little care about how you live your life.
That is how most millionaires/billionaires are made. The start up riches are an exception to the million dollar club. Everybody else goes through a pretty difficult grind until they make it.
You're talking about the millionaires who became right by saving their incomes. Their net worth will be in the low seven digits.
The folks with $10, $100 or $1B got there by either building businesses, getting incredibly lucky (lottery winners) or working as top execs in big companies.
For them, the sacrifice is not of money but of time. They don't wonder "gee, should I brew my own coffee and save $1000 every year?", but "gee, should I work on this deal right now or spend time with my kids?"
Sometimes an idea is so stupid that there's nothing really to say. "Billionaires are billionaires because they care about their cost of living"? It is just demonstrably untrue. Which is why we see billionaires with megayachts, penthouse suites, private jets, private islands, obscure car collections, etc.
Billionaires are billionaires because they've made amazing investments or have created companies or products worth billions. That's it. It has nothing to do with how they deal with their cost of living.