https://www.cnbc.com/2021/10/05/heres-how-much-teachers-arou...
What you really need is a comparison which is adjusted for both cost of living and alternative careers for comparable education. I described this as an underpaid profession because the combination of high demand, rigid schedule, and low respect is the primary reason I’ve known people to leave it.
The underfunding plays into two of those problems because teachers are asked to handler more, larger classes which ensures that everything is always close to the breaking point. The “slack” which that forces to be cut are things like personalized attention and more involved lessons.
As for retirement, most public school systems have extremely generous pensions. Illinois, for instance, has over ten thousand former employees with six figure pensions - not just administrators, but teachers, too.
Do you have any evidence American teachers work harder than teachers in other OECD countries? For instance, US class sizes are just under the OECD average, although this is skewed by China's unusually large class sizes, at about the middle of the pack and behind countries such as Japan, Germany, France, and Australia, and the countries with smaller class sizes aren't that much smaller. [1]
[0]: https://www.healthsystemtracker.org/chart-collection/health-...
[1]: http://www.oecd.org/education/skills-beyond-school/EDIF%2020...
Note that I specified teachers. A lot of that money goes to things like administrative overhead (often required by lawmakers) and support services for students — a single aide for a special needs kid costs far more than $15k. We run a lot of social programs through schools here which would be separate services in other countries which complicates these comparisons.
I mention that because I know a number of teachers here in DC. The public school pay here is high compared to the national average but not when you look at the cost of living, and most jobs which require multiple degrees but have inflexible schedules and long hours pay considerably more.