I wonder why SF/Peninsula SV knowledge workers have an expectation to live large at salary $X when many of their colleagues/friends are making just as much, whe

I wonder why SF/Peninsula SV knowledge workers have an expectation to live large at salary $X when many of their colleagues/friends are making just as much, whereas Manhattan New Yorkers do not have an expectation to live large making great money in absolute terms but still making relatively "average money" wrt relative income. I suppose one hypothesis is that the region has yet to come to terms with how widespread high earning power in absolute terms (but not on relative terms) have become.