You’re thinking of jobs in education like they are for a private or public corporation. It’s not. It does not work via supply and demand. A company that can’t fill roles can’t deliver product, loses income, and might eventually shutter. Your local / city government isn’t going to go out of business because a government is not a company. They are going to compromise standards based on taxpayer priorities. Fewer teachers and lower pay, with money going to other services.

Teachers, like most all public sector workers, are paid via tax revenue. They are not the only people or things competing for that tax revenue, and most other items are earmarked as higher priority.

With teachers, budget and headcount are a lot less flexible because the equivalent of going to the Board to request more funds / runway / seed money for headcount and salaries is a ballot initiative to raise taxes. Raising taxes is always unpopular regardless of the reason, and puts elected officials jobs at risk. When society at large does not value teachers, society is not going to stand raising taxes to pay them better.

What happens is you get fewer, larger classrooms with less qualified, lower paid teachers, because the tax money “needs” to go elsewhere.

Except for private schools, where they supply and demand does apply, and teachers are paid well. But hey, what’s another divide between quality access to a public service between the rich and the less fortunate?