From the article on pcgamer.com:

My understanding is that at the very least they still need to pay someone to administer the royalty payments to developers (me), respond to any administration requests from the platforms, update promo assets if the platform requires," Deery said. "AFAIK no one who actually helped publish these Adult Swim games works there anymore, so I figure they thought it just wasn't worth their time from a business perspective to maintain 'legacy' products."