I can't imagine where these "teachers" were "teaching"! In fact I wonder what century they inhabited. My experience in the 60's was quite different. I learnt a lot of music. Luckily I was taking violin lessons on the side, but even if I wasn't, I would have learnt to sing some songs and read music. Yes, I had an interest, but it was certainly taught.
Of course there were lots of students who just fooled around and didn't learn anything. I remember being stressed over my grade 4 class where we all had plastic "flutephones" and many of the kids refused to move their fingers appropriately so the whole thing sounded horrible. They just didn't have the drive to learn. I think that problem is worse in this century. Nevertheless, it has been my experience that music teachers are hard working, educated, and inspirational. It's a hard job.