I dunno. Remember these are still the early seasons before they decided they had to include some golden oldie in EVERY EPISODE. Unless they're having a problem with the in-house music guys like Alf Clausen (which I really doubt) I don't think that's the reason.
Isn't the fact that it's a cartoon and has SO many people involved and the fact that DVDs weren't even invented when the earlier seasons came out on TV have something to do with the speed in which the seasons get approved for DVD use? I'm sure they don't need everyone's approval who worked on the show, but there has to be a higher number then a normal television show. Or it could be the simple fact that they want to make sure EVERYONE has the current season before the newer one comes out. I won't be getting this Treehouse DVD if it only has 4 eps. They're on quite regurlarly around here, and I'll eventually have them when I get the seasons on DVD.
Gabe, I'm not sure how you knew about this, but thanks for pointing it out. Your name will be mentioned later today in a TVShowsOnDVD news item that will include the cover art for this puppy. Oh, actually retail is $14.98.
Jeff, can you please provide a bit more info/links/etc on how this is the case? Not that I don't believe you but I would really like to know what is going on. After all, I don't want to "Fox bash" unless it is necessary.