That's true for young kids, but not preteens. By that age they're old enough to stay home alone for a couple of hours after school. Hence the term 'latchkey kid'.
It isn't always a choice: Most child care places simply do not take pre-teens - they stop after elementary school, as do many after-school programs.
I'll also add that it isn't just a couple hours after school: It is holidays that parents don't get off work. It is summers without school. It is 6-8 hours after school while parents work second shift. It, in general, doesn't matter if your child is mature enough to stay home during the summer or late into the evening, the child care isn't for them.
Any gap in employment or long-term unemployment is difficult to get over, but staying home with children seems to have its own stigma. My mother had quite a problem with this: She stayed home as she could while we were growing up, occasionally working when we really needed money. She started working more when my brother finally didn't need as much care (my brother is 11 years younger, so there was quite a stretch).
She got told no because she didn't have recent work experience. Childcare simply doesn't count unless you are getting paid to watch other people's children.
That's true if you were just managing the home. I know that "homework" and caring for kids alone may sometimes be exhausting, but regularly allocating time for studying is usually worth it for everyone. I personally know two mothers who successfully changed their careers for better during their stay-at-home years.
