> Is there anything to prevent the pay for our most important and meaningful jobs from approaching zero?

The real blackpill here is that there's very little evidence that teachers matter at all. I mean somebody has to be there to supervise the kids and read from the workbook and it'd be nice if it were somebody trustworthy and reliable, so we might want to require proxies for that (like a 4-year degree), but beyond that the evidence just isn't there that it matters that much.

I reject the entire premise, in other words. Teachers do work that needs to be done, but they aren't individually important and almost anybody can do it. That's why the work isn't more remunerative. (Although it actually pays quite well (in the U.S. at least) for what it is.)