My wife's a teacher and neither she nor her collagues have to do this.

All the teachers I know (three in my neighborhood) don’t do this. So I guess we know different teachers.

The US pays teachers pretty well compared to other countries [0] but that doesn’t mean that all areas pay well.

[0] https://www.businessinsider.com/teacher-salaries-by-country-...

When I graduated in 2008 teachers were doing this. Most I knew had second jobs in the summer. Never really heard of teachers using the summer as a vacation unless they had a spouse who made more money.