They will probably resurface somewhere. While HBOmax was shelving some content for good for tax write offs—this is probably about selling rights to the highest bidder.
I've read a couple of commentators speculating that the cartoons will go to one of those "free ad-supported streaming television" (FAST) platforms like Tubi or Pluto. The ad model is supposedly more profitable for stuff where people will put it on and let it run for hours.