Spiegelman also started RAW, which supported new voices And experimentation which opened up new avenues and innovations for Comics. Crumb folded in the hippy counterculture into comics (though he wasn’t the first, but he made it popular) and Panter did the same with the Punk counterculture, that’s why I believe he is there. Ware is a stellar draftsman and has a unique way of putting the whole history of comics into a singe Page (when he’s on) and making it something personal at the same time. To me Ware is comics entry into post-modernism.
Anyway, that is what I took away from their inclusion, just my opinion.