Krenkel was a proto nerd and was active in sci-fi fandom and knew a lot of guys in sci-fi fandom. This was long before it became cool. Editors in the sci-fi world wanted more work from him, but he just didn't have the drive or confidence or discipline to be a professional. Krenkel was a much beloved figure by all who knew him and he kept up contacts with a lot of sci-fi and fantasy artists, writers, editors, and fans in and around New York.
I can't answer your other questions. Not sure if I understand them.