To a certain extent all humans are materialistic and modern humans the most. I did read a letter Howard wrote to a friend when he was still a teenager in which he was proud of making a few bucks promoting a scholarly talk. Do keep in mind that Howard cast many of his villains as monastic types laboring under vows of poverty. His wizards cared nothing for jewels and gold. Even asshole writers who defy editorial advice like to sell books, because money brings more freedom to write and because we would not write if, on some level, we did not seek approval for what lurks between our ears. In America, in Howard’s time as in ours, there is no greater statement of approval than sales—money.
That said, and he did well by the standards of the day, actually making a living as a writer, Howard demonstrated a great deal of intransigence when it came to conforming to editorial tastes. There is no better example than The Frost Giant’s Daughter, first written as Gods of the North, which Howard did in three versions, unable to sell any of them, to the man who had already bought into his heroic vision. Howard did not take the obvious step and cut out the rape of the goddess by the hero, as the core of his story was pure offense, man against the gods.
The number of Kull, Bran Mak Morn, Solomon Kane, Conan and Black Vulmea stories that failed to sell is appalling in retrospect. I guarantee you, however, that Howard could have reworked most of them into saleable form, but chose to give up on the specific inspiration—for they seem to have come into his mind whole—and retain an element of that tale in another, such as he did with The Vale of Lost Women and Iron Shadows in the Moon, the later taking on key concepts from the former.
Howard rewrote a Kull story as a Conan story, a Conan story as a Black Vulmea story, an Amra story as a Conan story, and had less success than failure in selling these attempts to better commercialize these tales. I think that is because, even though he sought commercial success, he was only willing to compromise so far.
I think—and it is a sense derived from examining his body of work, because I actually know little of the man—that Howard was, in his writing in the shadow of editorial concerns, much like his heroes were in terms of their fighting in the shadows of civilized conventions. Just as Conan engaged the civilized West to the point of becoming one of its kings, he also failed to adapt to the point of experiencing a disastrous reign [as did his prototype Kull] with two battles lost by conspiracy, a near successful assassination plot and twice tossed into a dungeon in chains.
Howard’s other heroes likewise suffer for not compromising, with Vulmea and Kane being two stark examples.
Howard was torn between two worlds, just like his characters; his physical ambitions played out on paper and their barbaric proclivities played out in a world of civilized sensibilities—both the reader and the setting exemplifying the circumstances his heroes strove against.
He: Gilgamesh: Into the Face of Time