What I'm noticing from that list is that there were a lot more individual cartoon shows than there are now. Since the networks aren't doing them it is up to Cartoon Network, Nickelodeon,PBS and a few smaller ones. They rely on fewer shows with more repeated broadcasts.

Back then you also had to make choices because if you watched the Gary Coleman Show (Hornswaggled!) You might not get to see Gilligan's Planet in reruns unless you watched the TV Guide very closely to find out when your episode was rerunning.