Housing is what makes the coasts costly. Other expenses are roughly similar and more than compensated for by higher earnings. Sometimes they can even be lower, like health insurance or certain goods or services. Because housing is so variable it's difficult to say which is more affordable without specifics, but the higher your disposable income the more likely it is that working in a coastal city makes more sense. If we both can save 20% each year for retirement or kids' college tuition, my 20% will be much larger than your 20% given the often times huge disparity in absolute earnings, and even my 10% or 5% might be more than your 20%. The price of a condo in Florida or Arizona is the same for both of us. State college tuition is also much more similar across states relative to earnings differentials.
Most people rationalize their decisions to stay put or somewhere familiar. If they didn't, most retirees would have moved to Ecuador--social security and pension payments are the same no matter where you live.
https://www.census.gov/quickfacts/fact/table/sanfranciscocou...
You clearly haven't dealt with the cost of the bay area before. Your dollar's purchasing power is cut in half compared to the Midwest.