In the US, most professors are part time adjunct and get no health benefits. Probably make 30-50k.
Tenured faculty at major universities make 70-90k.
Considering these jobs requires at least 9 years of uni (in the US), the lifetime income of professors is still very low.
RE TAs: I US stem fields TAs work 20h and make 15-30k. That usually includes free tuition, but not in all states (e.g. in Texas, you sometimes pay tuition out of your TA pay, which is crazy)