I had that very discussion with a co-worker leaving. They told me working wasn't worth their time, and they'd better care for their home, family, themselves etc. instead.
And it wasn't that they were rich or their partner had a high paying job, more that the cost of daycare, private teacher, eating outside every day, work related stuff (clothes, commuting etc.) and their general health and mental impact made it a net negative for them. Working a job they didn't enjoy just didn't make any sense.
The interesting part to me is that the calculus didn't change overnight, it's more because one day they stopped for a while and thought long and hard about their life, and came to that conclusion that was there for a very long time already.