just an endless pursuit of materialism. you want something so you gravitate towards it. hence a lot of regular people are destroying their financial futures by staying in these super expensive areas.
Destroying their financial future? None of my friends living in SF or NYC make less than $160k a year working as engineers. In fact, they make that nearly right out of college. The more senior engineers (5+ yrs exp) bring in $300k-500k a year.
They save a significant amount of it, more than they would have saved in any other place. And they can leave at anytime to a low-COL place and buy a house in cash.