I have heard that part of the reason our district tops out at AP Calc BC is a lack of qualified teachers. The kids are ready for Algebra I in 7th grade but the district has to slow them down so that the lack of a teacher for MV calculus and above is not an issue. We are a smaller district and do not attract a teacher, or enough students, to have a full time teacher employed at that math level. 1/3 to 1/2 of each class takes Calc AB but not all get the required 5 on the AP exam to be permitted to enroll in Calc BC senior year. 1-3 students a year do online courses to go beyond Calc BC.
Calc AB is a class that goes over the top with HW. It was suggested that my son give up ECs if he did not have 2-3 hours to spend on the homework EVERY DAY. I will never know for sure since I am not in the classroom, but it sure sounds like an expectation of self-teaching to me.