What aren't some of the specials on DVD?

I looked thes eup on Netflix and just watched Disc One of 1976-1977. The first disc contains "Francesca, Baby" and "Beat the Turtle Drum" (I forget its original title).

Some of these I did not see when they were on TV, but I seem to remember some of them being shown to us in school (I wonder how since there were almost no VCRs in the early half of the 1980s). I know I saw "Pinballs" in school. It's on Disc Two of 1976-77 and I have that one in my queue next. I believe I also saw the one with Jodie Foster playing baseball in school, too, but I did not see that one listed as being on any of the DVD releases. And why are "My Mom's Having a Baby" (I rememer that one) and "Where Do Teenagers Come From" (I believe I saw that one in 1980) not on DVD? And what about the one from 1987 about a boy with AIDS?


Each DVD release is a two-disc sereis wiht only two episodes per disc.