What would a FIRE Zoomer teach their children, especially if they invested in crypto early and got lucky? Why work hard if mom and dad "don't" work at all? Why go to college if the point of college is training for a career? How will those children be shown by example how to be a helpful member of society?
I suppose a lot of FIRE people likely intersect with the Child Free crowd where they are achieving financial independence by not having any expensive dependents they need to care for. That does reduce the amount you must spend by quite a lot, but if enough people do it the economy will have issues finding workers at all as more people voluntarily check out of the system and leave no descendants to continue in the future.