You see, back in the early 80's Moon Knight wasn't a "C-List character at best". The book was something of a sleeper hit at the start there and the Moench/Sienkiewicz run was stellar. It did so well that it was one of the first small handful of books Marvel made direct only and started to print it on better paper using more than 4 colors. Sienkiewicz started as something of a "Neal Adams knockoff", but really started exploring his style during this run and his later run on New Mutants to become something altogether unique. And that work cemented him as an illustrating legend.
"C-List character at best" - LOL. You guys kill me how you say these things with no idea of the real history involved.