Why don't we get paid for allowing students to rotate with us?

Outside of academic institutions, where educating your students is obviously part of your responsibility, we are often asked to take on DO students or PA/NP students. There is never any discussion of payment, which continues to blow my mind. Students make me less productive and are a big drain on my energy at work. I personally do not accept students, but often end up with them because someone else in my group accepted them. Meanwhile, their schools are still charging them tuition for...what, exactly? Why do we still allow this, and is anyone aware of any efforts to change this?