What an awesome topic. My father, who was a youth during the Great Depression, would tell me stories about the radio broadcasts he and his sister (my aunt) would listen to. Virtually all of that pre WWII stuff is gone because it was never copied in the first place. What a damn shame.
I looked for fault in your list but couldn't find any. George Burns, who did it successfully in both radio and TV, is a worthy #1. Other great ones not listed were the Mercury Theatre on the Air and Campbell Playhouse (both Orson Welles) as well as the Screen Guild Theatre.