I mean, everything sells poorly except for Spider-Man, Batman, Star Wars, and various combinations of those properties.
I argue that major publishers and the direct market are more predicated on not seeing them as a strong profit driver and so they don't really try on the format. There's nothing really preventing a collection featuring something like Sensation Comics Featuring Wonder Woman, Adventures of Superman, and Legends of the Dark Knight in the same book alongside some smaller stories. Essentially, the industry has taught a specific demographic that this is what we offer as a norm and in doing so, alienated other demos. We sold pulp magazines until we decided pulp magazines weren't the thing we were selling anymore.
It's like manga. For the longest time, manga was either not published on Western shores, or sold in odd-cut floppy format. It wasn't that a market didn't exist for translated manga in the tankobon format, it was that existing publishers and retailers didn't try hard enough to sell the different format to new or existing audiences. Once someone really dug in, the format took off. And note, it flourished outside of the direct market, where the market itself wasn't trying to force the content to fit its existing format.
