Yes, just what we need, retired people with a whole career of making income behind themselves taking another decent entry level job someone one just out of college can get. (No teaching credential needed for substitute teachers usually)

If a semi-retired engineer with 2-4 decades of work experience makes a better public high school STEM teacher, then I hope a lot more engineers do it as a semi-retirement gig.

The aspiring career schoolteachers will just have to find a job in a field that is short-staffed, like registered nurses or one of the trades. I'm sure that comes across as "let them eat cake" to some Bernie moron, but going back to school for 6 months is small potatoes, and doing a little market research before making big financial decisions like choosing your college major in the first place is basic adult responsibility.

If we apply the "lump of labor" fallacy everywhere else honestly and consistently, we would have to be opposed to immigration and trade because "those damn foreigners" went and "took er jerbs".

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRtkJaZ...