Having a PR guy seems as wasteful to me as having an agent in porn. If you're any kind of hustler, you don't need that shit. The ho's that are good at twitter can cover all bases themselves
That's just it, many performers do not want to be bothered doing their own tweets, FB messages, forum posts, etc. It's easier to hire someone so they can enjoy life while the slavering fanboys are left unaware. Not all of them cost $1000/month either, especially now with so much competition but even C3X is making money running some of their accounts, remember?
But over the years, I've been made privy to all sorts of comments regarding "oh that's just my publicist/friend/agent/etc posting for me", the ADT forums huge with that kind of thing before twitter and other social media took off. The stuff that goes to the industry is good for garnering attention of directors, producers, and such while the stuff going outside nets website memberships, "dates", and the like, to pay the bills. It's just part of the game.