I bet mobility is part of why nursing and teaching remain ultra-popular for women. They offer more flexibility than normal for time off for raising a family, and both are remarkably good as a supplementary job to a higher-earning spouse, because of their relatively high mobility—every place has schools and hospitals, more or less, and if they don’t there are no other jobs there anyway. Good options for the do-both-career-and-semi-traditional-family-thing set, which is probably a pretty large proportion of preferences (not saying a majority, but enough to explain the high interest in those careers)
Nursing’s the better of the two from that perspective, but re-licensing as a teacher in a new state is usually not that bad, and once you’ve got that you will find a job if you’re anything but terrible at it.
My wife teaches Chinese, and this is spot on our situation. Schools and language centers are always hiring. She usually has 1-2 private online students she tutors (generally adults who are learning Chinese for fun). As long as she commits to a semester at a time and doesn't leave in the middle of her semester, she can always return to her job. If we have kids, she can go part-time or be a full-time mom for a few years. Every school teaches the same stuff, so it's not like she has to "keep up" like I do as an engineer and learn new things every few years.
Her income is a lot less than mine, but the extra cash is nice. We've set up our life so we don't NEED the money she brings in so if it ever goes away we'll never panic.
Nursing’s the better of the two from that perspective, but re-licensing as a teacher in a new state is usually not that bad, and once you’ve got that you will find a job if you’re anything but terrible at it.