For one, there haven't been many animated series released on DVD from other companies with the exception of more action-oriented shows like Transformers or adult-oriented shows like The Simpsons.
Although this quote is "Octobery 2003" old!...LOL, that is very un true now, shows such as Garfield and Friends, Pee Wee's Playhouse, The Raccoons, Ren and Stimpy, and older classic cartoons such as Looney Tunes, Rocky and Bullwinkle, Wacky Racers, Fintstones, Scooby Doo, the Jetsons, Top Cat and so on. More cartoons are bound to come, not all will be full sets or seasons like recent Fat Albert. But more and more cartoon/kids shows are coming to DVD.
I don't know what Disney's plans are as they own the rights now but I hope they eventulay do, they really should start putting DVD's of there own shows out now, like DuckTales, TaleSpin, Gummi Bears. Maybe it's because they still play them on Toon Disney...er well, not Gummi Bears anymore for some reason....but they don't play the classic's as much now with the newer cartoons about kids, kid super heros, alien's, talking dogs, and teenage witches all going to school.......But back to dvd's, it's not just Simpsons, Family Guy and Kind of the Hill. I'll bet will get much more in the years to come, with the talk about the new CGI Chipmunks movie....yuck! but it could bring the shows classic and the newer 80's one to dvd. it worked for Garfield, Rocky and Bullwinkle, and even Fat Albert!
I could seem the Smurfs, RugRats, Peanuts and many other cartoon toons to come to dvd with in the comming years! it's so cool! Plus we all know Fraggle Rock and the Muppet show seasons ARE coming!
As for the rights to the many clips of films in Muppet Babies, wouldn't you think they would already be paid for? look at all the songs in The Muppet show and eps of that were put on DVD, i don't think they had to pay out each right to the song on the muppet show, they would be chopped up more the MFC if that was the case!!!

I don't know for sure but i would think it would already be paid for, seeing as shows were released on video before.