That's the problem, they don't want kids to actually learn. They view teachers as glorified babysitters.

This. A lot of districts are also trying to add some computer science curriculum but can't find anyone to teach it.

60k is extremely low for CS grads in any moderately-sized city but they might be willing to make that trade for two months off in the summer.

Schools wouldn't hire math grads even if they could pay them six figure salaries. You'll just end up paying the same type of people you have now six figures.

No one needs a math grad to teach 3rd grade math. That would be a huge waste of money and expertise.

More specifically, teaching is a different skill than knowing. Excellent math teachers are very different than math majors - in some ways it’s less complex (eg pushing the boundaries of the field of mathematics), and in others it is far more (understanding the human psyche and how to effectively communicate abstract concepts).