While teaching may be a rewarding career, I can’t fathom a real engineer getting any job satisfaction from teaching HS kids

One can still do engineering, on their own time. A 9-5 job doesn’t have to be ALL that you do. Also, if the school has money, you can end up playing with some really cool toys, and having students play with those toys as well.

Plenty of brilliant people worked as a teacher or a patent clerk and did amazing work on the side.