Most ranges are Clubs. Most Clubs are private, Members-only sorts of places. The commercial ranges probably have their own instructors and classes.
My Club holds LTC courses, but not for the financial benefit of the instructors (all volunteer); the $ that's raised goes to the Club.
I'm guessing that most places have a similar attitude: why should the Club incur the loss of range availability, wear and tear, etc. for the benefit of an individual, especially a non-Member? Not trying to be a Richard, but this subject comes up about once a year.
Hell, if I had to wait to shoot on the range my dues pay for, because some non-member is hosting a class, I'd be pounding the table at the Monthly and BoD meetings, and I'm about as mellow as you can get.