You're looking at the wrong thing. Don't look at the topic of their work; look at their cognitive style and overall generativity.
By generativity do you mean "within-domain" generativity?
Carmack is many levels above Pearl.
To unpack which "levels" I was grading on, it's something like a blend of "importance and significance of their work" / "difficulty of the problems they were solving", admittedly that's still pretty vague. 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. And for that "style" isn't especially relevant. (This can also be true even if Carmack solved many more problems.)
But I'm curious about your angle - when you say that Carmack is many levels above Pearl, which specific dimensions is that on (generativity and style?) and do you have any examples/links for those?
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.