"Barely literate fans" say from Robert Bloch to Stephen King to Brian Lumley to name just a few, who extended the Cthulhu Mythos, and were deeply influenced by HPL?
Yeah, as a stylist his work leaves much to be desired. And he knew it. He knew, for example, he couldn't write dialogue to save his life, so his work contains very little of it.
It's difficult to describe the appeal of HPL exactly, & I'm not going to take the time to try. But, I can't imagine why someone would read the entire oeuvre of an author for the sole reason of reveling in shitty prose.
'Sup with that shit?