It's not that teaching isn't "popular" - it's simply that there are all that many jobs available these days. Teaching English is usually looked at as a fallback option, but you're competing with plenty of native English speakers from the UK who have the right to work anywhere in Europe, and thus come ahead of you for any job opening. Getting into the public school system can be next to impossible in countries where teaching is a "civil service" job.

Insurance can be tricky as national laws vary quite a bit - and in much of Europe, "life insurance" is an investment vehicle rather than "insurance" as we know it.

The trailing spouse thing seems to be pretty much the case universally, at least throughout Europe. There may be some ways around it, depending on the line of work of the trailing spouse and if he or she can find an employer interested in hiring them after the family has settled into their new home.

The job situation right now is dodgy in just about all fields, but hopefully something will free up in the 4 or 5 year time frame you're considering.
Cheers,
Bev