I think you make an accurate point that people who teach (who are capable enough to have other options) are probably not motivated solely by the financial rewar

I think you make an accurate point that people who teach (who are capable enough to have other options) are probably not motivated solely by the financial rewards. But there is nothing about teaching that would prevent a top teacher from earning $250K per year. The reason that doesn't happen (and the reason we don't see more luxury cars in the teachers' parking long) is because unions have forced wages to be based on seniority and not based on merit. This means that rather than one teacher (a good one) making $70K and another (not so good one) making $30K, they both make $50K. This gives the bad teacher every incentive to continue being a mediocre teacher for decades rather than moving on and finding a career he/she is good at.