First off, I will say He-Man was NOT and NEVER WAS Saturday Morning.
Though it seems like in the context of what the guy's going with, I suppose lumping in weekday morning/afternoon cartoon block works just as well.
Upon the history part, the actual first show NBC did was called "Tele-Comics", while Crusader Rabbit was initially pitched to NBC (aside from also airing on its West Coast flagship), as it was syndicated to other markets outside network programming.
A lot of early attempts at sticking anything animated on for kids during the 1950's often ranged from silent films from the 1910's and 20's with added music scores to repackaged/redubbed foreign cartoons, mainly from Europe. It was really trying times for any local station that had to set up a kiddie show hosted by a cowboy, a space cadet or a clown to show stuff like this...
Crusader Rabbit was a first in trying to bring something 'animated' to the small screen in the best way possible due to the budgets provided. A lot of this is dealt with in Keith Scott's great book on Jay Ward called "The Moose That Roared". Other such forgotten gems followed like Spunky & Tadpole, Bucky & Pepito, Paddy the Pelican or even Jim & Judy in Teleland (and I'm not making up these titles, look 'em up!). It really took Joe and Bill's "Ruff & Reddy" for the formula for effective limited TV animation to take off. The 1960's was technically when Saturday morning really happened when a day set aside to place these shows at all. Parents were still in bed for the most part back then like all good suburbanites were.
In another video, I do believe he mentioned (live) action shows being why a particular network fell apart. For this one, he brought up four things that contributed to the downfall Saturday morning cartoons:
1) Rise of technology
In fairness, who wouldn't. Even my family had all the video consoles and a VCR in the early 80's. That Panasonic ad reminded me this was our first VCR we ever had, though it was re-branded as a JCPenney's instead (because people still bought things that way)! I still got this damn camera!
This one was rather gradual. Much like the early days of TV in America, the same could be said for cable TV as well. Nickelodeon in particular was nothing like the powerhouse they were after the 1990's, so their initial output often included tons of foreign toonage we couldn't get anywhere else there! USA Network was once known for their "Cartoon Express" block, which was mostly dominated by older Hanna-Barbera product before more original productions started to replace it in the 90's.
Afternoon cartoon was not a new thing in the 90's, but in terms of 'original programs', that really started with He-Man in '83, since syndicating cartoons on weekends usually was filled up with older theatrical shorts like those from WB, MGM and so-on, an occasional rerun of The Flintstones or another network show from Saturday morning's past might also be seen like Underdog.
The 1990's was when it really exploded for these new avenues to happen.
3) Angry parents (A.C.T.)
No doubt there's always going to be angry parents in any era. If it's not violence, it's sugary junk food and marketing things to children that they despised. This is why certain countries like Norway decided to have none of it.
In all fairness, Romper Room was sponsored (and later bought) by Hasbro anyway. It's syndication arm, Claster Television was later responsible for those later shows like G.I. Joe, Transformers, Jem and so-on.
4) FCC regulations (from 1990)
I blame SyndEx, it ruined WGN!
https://en.wikipedia.org/wiki/Syndication_exclusivity
Although I wouldn't doubt that lack of diversity in cartoons may have also helped.
I'm sure of that.
I think a big part of that is that kids were driven to the cable networks by the relative monotony of the major networks, and they never came back. By 2001, let's say, Saturday morning was dead.
Yes, that was monotony that make cable seemed so appealing.
A lot of these cartoons haven't gotten proper home video releases because they are owned by companies who are totally indifferent to them. There's always hope for the future, though.
When it comes to certain companies like NBCUniversal, I'm not holding my breath.
I remember seeing a few of those shows back on TV, but me being a Canadian, I could just simply catch them on YTV (as they aired most of those mentioned in the press release). The others I never even saw until the advent of YouTube.
Saturday morning didn't seem to be a Canadian thing as I noticed stations seemed to like sticking stuff on weekend afternoons for kids instead of mornings in earlier years. Someone I know chronicle how CBC used to ran the Bugs Bunny/Road Runner show at 5PM during the 70's.
http://www.kevinmccorrytv.ca/bbrr.html
To me, Saturday died in the mid-2000s when YTV started shifting their action shows to the afternoons and they dropped a huge chunk of their library (They're how I managed to see shows like Jetsons and Rocky and Bullwinkle on Sundays, but that's another matter for another time). And by the late 2000s where they just became SpongeBob-reliant, they were going down further and further.
Yes, it happened.
Also, because I can't find the main Simpsons thread:
Quite fitting anyway, love how they set this up!