Seems to me that working 40-50 hours a week for 10-15 years at high pay is a more reasonable situation. Then have a big enough nest egg to do what you like, a la mrmoneymustache.
Except life is now and cancer sucks. Also assumes you were able to achieve a high paying career and not some dead end job that only pays enough to keep you alive.
the problem is that it's never enough. One day you have kids and your expenses go way up, another day you buy a bigger house with a bigger mortgage, next thing you know 15 years is 40.