Asking a student to practice 20 minutes a day is asking them to be as dedicated as music majors?

Then isn't asking a student to practice 4 or more days week for a sport asking them to be as dedicated as a professional athlete?

In band, practicing is your homework. I don't understand why practicing an instrument as homework has become so taboo. If you can find time to do the homework in other classes, then time can be found to do the band homework also.