It's not, though. Median rent in Mountain View (significantly pricier than San Jose) is now $2390/month [1]. L4 total comp at Google, or E4 salaries at Facebook, is about $260K/year [2]. Average rent for a 1BR in Dallas is $1250/month [3]. Average total comp for a software engineer in Dallas is $110K/year. [4]
After taxes and rent, the Facebook/Google L4 is making $260K * (1 - 0.37 [5]) - 2390 * 12 = $135920/year. The Dallas SWE is making $110K * (1 - 0.16 [6]) - 1250 * 12 = $68939/year. Even with the $4K/month rents from 2019, the Facebook engineer is still putting away $116K/year, more than the total gross of the Dallas engineer.
People tend to underestimate the effect of the top-line on finances and savings. Eric Schmidt had a saying: "More revenue solves all known problems". It applies as much to households as to giant companies.
[1] https://www.zumper.com/rent-research/mountain-view-ca
[3] https://www.zumper.com/rent-research/dallas-tx
[4] https://www.indeed.com/career/software-engineer/salaries/Dal...
[5] https://smartasset.com/taxes/california-tax-calculator#vyY8q...
[6] https://smartasset.com/taxes/texas-tax-calculator#s0LEbwxtAs
You're using average (median I hope) salary for Dallas vs. high end salaries for San Jose.
You used indeed.com for the Dallas salaries, if you use them for San Jose you get an average of 150K. Too lazy to run the numbers but obviously that would change the calculation quite a bit.
Compare Facebook salaries in San Jose to Facebook salaries in Dallas, that would be a fair comparison. Compare median salaries in San Jose to median salaries in Dallas, that would be a fair comparison.
Compare Facebook salaries in San Jose to median salaries in Dallas, that is not a fair comparison and you know that, you are wasting my time by making me type it out for you, you know full well that that is not a fair comparison.