Yeah, but what does that really mean?  Warner Bros. managed to find a way to put out Pirates of Darkwater, yet Disney can't manage to find a way to put out Gargoyles?

It could be an issue of Opportunity Cost.  Actually, that article isn't the best explanation for it I've seen.  If you have y products you could sell, and you have factories that can make x products, and x < y, then you need to choose the x most profitable of your products to sell.  If you made another product, even if it was profitable, it would cost you the money that you could have made by making a more profitable product. 

I think this explains why (physical) videogames go out of print.  Nintendo does not have endless factories for making endless products.  However, for things like Steam, where there is no cost for selling an old game and hence no opportunity cost, it can be profitable to sell old games.

So, anyway, even if Disney could make a profit selling Gargoyles (and it's hard to imagine they couldn't), there still might be an opportunity cost if they could just pump out more Pixar DVDs or something.

On the other hand, I don't know if Disney's decisions are always explicable in terms of standard economics.  They are known for releasing movies for only limited amounts of time.  I think they want to keep the "prestige" of Disney up.  They might think that a print-on-demand DVD looks shoddy and would damage their image or something.