Frazetta, Woody and Norman Mingo. Somewhere, Bill Gaines is smiling.
Gaines paid for quality artists. And he held onto the artwork for decades. By the 1950s and 1960s, EC stories were already being reprinted (first the Mad Comic Book stories in paperbacks, then Tales From The Crypt etc in paperback form).
By the 1970s, Russ Cochran started reprinting individual issues of EC Comics and by the late 70s or early 80s he was reprinting the complete works in hardcover slipcased editions.
They never have gone “out of print” (some series yes, but there is generally some work available).
And I think that the artists got money as the artwork was released to the market in the 1980s/1990s. I don’t think that the artists were outright given their artwork though (including Mad Magazine artists).
This top selling Frank Frazetta drawing meant something to Frank. He bought it back from Bill Gaines at the time in the 1950s (I don’t know how much he received for its publication).