We've tried the "keep giving the system more money in the hope we get better teachers". We've been trying that for my entire life. If you want to pay teachers like SV engineers, you're only going to be able to do that in the general framework of a for-profit company.

If you imagine a really competent teacher sitting next to an engineer with the Khan Academy and intensely working with them and the statistics to produce a high-quality course, that's definitely the sort of thing that will command an SV engineer salary. There will be fewer such positions, but the immense societal gain of having these high-quality curricula propagated far and wide for cheap will far outweigh the fact there are fewer teaching jobs.