I disagree that
no 20 year old thinks that much about money.
If you're lucky enough to have had rich enough parents to not have to worry about money too much, yes, you'll probably optimize for doing things you enjoy, but people who spend a lot of their younger years with money issues will sometimes obsess about it and really focus their lives around 'getting rich'.
I've noticed have similar phenomena with people who are deprived of certain important needs in their youth - people who are starved of a certain type of parental affection overcompensating by orienting their lives around getting more of it (eg women with daddy issues who are very promiscuous), people who feel disrespected and downtrodden who become obsessed with social status, people who get bullied and get into martial arts...
If you've ever read Gone With The Wind, there's a line where Scarlett O'Hara says "with God as my witness, I'll never go hungry again". I suspect that many people who have similar experiences will react by orienting their lives in a similar manner. "I was deprived of something important, so I will react by over-indexing on that important thing I was deprived of, to avoid the future pain of being again deprived of it".