The real pulp fiction is any fiction published in the pulp magazines. Lovecraft had stories printed in Amazing Stories, Astounding Stories, and Weird Tales, so he was most definitely a pulp writer. As were Long, Derleth, Howard, Smith, et al.
It's the gamers who have tended to restrict the concept of "pulp" to the action-adventure brand of pulp fiction. But you could just as easily make an RPG about romances in the old west, college sports, or defective detectives and call it a Pulp RPG.
Right now, I'm hard at work on an RPG based on the legendary pulp magazine Strange Suicide Stories. One-off adventures only, though; the topic does not lend itself well to campaign games.