I know a few teachers who have quit or want to quit. It isn't a money issue, at least for them. My high-school computer science teacher (many moons ago) taught advanced high-school math. He quit because the administrative requirements became too burdensome. He loved teaching, but every year the administrivia got worse until he finally quit. Another teacher was a special-ed reading instructor; that's what she was trai…
I work at a school that improved during my time. We've enjoyed some changes that brought the school significantly more funding, and it has allowed us to attract better applicants, and hire additional staff members that help take some of that load off the teachers.
Also, simply having more adults per student makes a big difference, provided they are the right adults for the job.
Your friend was forced into the wrong category because of a funding problem.