I'd call Florence Nightingale a 100x nurse, or maybe a 10,000x nurse, for the impact she had on the world:
https://en.wikipedia.org/wiki/Florence_Nightingale#Statistic...
The 100x teacher who molds the mind of the kid/teenager/adult who eventually cures cancer is worth more than just about any single 100x developer out there right now, and you'll never know that person's name.
(Yeah, I'm aware there will be multiple different cures for different cancers, the point remains)
Another way of saying this from a mercenary monetary point of view is that I don't think investing more than $250K/year on a K-12 teacher makes sense, though you might be able to make an argument that people who teach teachers might have greater leverage.