Professors don't collect money from undergrads to pay for research; they collect grants to fund themselves, their students, their labs, etc. They spend a tremendous amount of time and energy writing these grant proposals and submitting them to all the right people.

The reality is that most Research Professors (not all professors are on the tenure track, after all) are more motivated by research than by education, because they have to be. Nearly everything is stapled to #/quality of publications. If you don't like that, you'll have to revamp the whole system.

Besides, as much as we glorify it, teaching students sucks. Students do the bare minimum it takes to get the grades they want, and exhibit next to no real interest in the topics at hand. Add on to that that the professor has likely been researching an offshoot of this topic for years or even decades and you don't exactly have any motivation for the professor to put himself out there for the student.

If you want a professor to really care about you and make an active investment in you, you have to engage with him or her somewhere outside of class. The best way to do this is through research. If you want to put in your minimum to get your diploma, you're going to get that professor's minimum as well.