There was a lot more to it than that, but yes, he found that very frustrating. I think you'd all find this interview from May 2007 interesting:
Writing the Books He Wants To Read: Robert R. McCammon | Julie's Portfolio
Two is "a lot"? Those are, really, the only McCammon books that are similar to King books in any way (and he acknowledged in a 1987 interview that
'Salem's Lot inspired
They Thirst: "Yes, I was influenced by
'Salem's Lot. It made me wonder what I could do with the vampire scenario. I thought: if Steve King can do a vampire novel on the scale of a small town in New England, I can do one on the scale of a major city.")
Robert McCammon » McCammon Interview: Footsteps, November 1987
People also like to compare
Boy's Life with "The Body," but as far as I know, McCammon never read "The Body." In any case, any similarities, IMO, boil down to the fact that King and McCammon are close in age, and they grew up with pretty much the exact same influences (Bradbury, Matheson, '50s and '60s horror movies, etc). They're both writers who excel at creating characters who live and breathe.
Hunter