If you can build a satisfying life and career somewhere cheap, why wouldn't you just do that from the beginning?

Is it really worth it to take a crap standard of living in SF over several years for, what, $5000/year in investment income?

Right sorry. That is still only $95k or so if you are paying Californian + federal taxes and pay toll taxes.

Exactly. Parent is exaggerating. Also, highest tax bracket is 37% (2018). Yeah, I'm arguing about 1%, but that's also for individuals making over 500k, or couples making over 600k.

50k to 100k income raise bumps you up 2% in tax rate from 22% to 24% (assuming individual).

If parent was talking about raise on top of what they have, then the worse affected rate of change would be the 24% rate ($82,501 to $157,500) to 32% rate ($157,501 to $200,000).

These numbers are similar, but less affected with MFJ.

Not really - the same tax dollars buy less service and infrastructure when the workers and suppliers also need to function in high CoL areas. A $2.5bn mile of subway in New York isn't a priori better than a $600bn mile of subway in Seattle. A $59k entry level teacher in San Francisco isn't a priori better than a $33k entry level teacher in Wisconsin.