By generativity do you mean "within-domain" generativity?
Not exactly, because Carmack has worked in more than one domain (albeit not as successfully; Armadillo Aerospace never made orbit.)
On those dimensions, it seems entirely fair to compare across topics and assert that Pearl was solving more significant and more difficult problem(s) than Carmack
Agree on significance, disagree on difficulty.
In light of reading Hazard's Shortform Feed -- which I really enjoy -- based on Raemon's Shortform feed, I'm making my own. There be thoughts here. Hopefully, this will also get me posting more.