A tenured professor though can get $20k per class or more, assuming that he/she is only teaching and not involved in any research (most start with 3 courses per

A tenured professor though can get $20k per class or more, assuming that he/she is only teaching and not involved in any research (most start with 3 courses per year). Of course many tenured professors also bring money to the university through grants and whatnot, but that is not always the case. I know of some that get more than $250k a year just to provide prestige to the department and maybe teach a course now and then. In any case, it doesn't matter if the class size is 10 or 50. You still need to prepare the same material, you still need to be there for the same amount of time. $3500/class sounds like a bargain to me. A TA earns more.