I responded when you posted essentially the same thing in another thread. Here is what I wrote there:
You are describing the least effective mode of teaching and holding it up as an ideal.
The next step was home study, where the student when through carefully designed materials and then went to a class where the instructor would go over all that with the students. I started teaching that way, and, ironically, we still spent two 4-hour sessions, about the same total time as you describe. I worked very hard to make sure my students understood, and I would not start the final exam until I was sure all of them would pass. I usually got all students over 90% that way, and I never had a student below 80%. I was proud of that.
Then came online learning. Students would arrive with certification that they had passed the online class. We would spend an hour or so going over everything to make sure there were no real problems, then give the final exam. I think I went through about a dozen students that way before I had one miss a single question on the exam.
That covers the academic material. As for the performance requirements, almost all agencies are members of the WRSTC, which defines minimum requirements for ow instruction, and those have not changed much at all in decades. About a dozen years ago, PADI issued new standards for the OW class. Those new standards did not remove any of the old ones, and they added about a dozen new requirements. In all likelihood, modern students are expected to do more than was required when you were certified.