At least the one I was on did. It's because a quarter of the people in an rp guild are leveling up alts and playing out their rp fantasies and don't really care a ton about progression. Half of them are mildly interested in RP and do it for fun, but also take the game seriously and try to progress through end game content, then there are some who were RPers but now don't really care and are in the guild for the friends they made and to help out with end-game progression. That was my guild pretty much in a nutshell (Midnight Reveries). Very friendly atmosphere, just people chatting, occasional RP games.

However, my server (Venture Co.) was terrible as an actual progression server, at least the alliance side was. It's because no-one in my guild/server side was willing to raid more than 3 or 4 times a week, for 2-4 hours a night. Whatever though, I played for fun when I was playing, pretending to be a pink haired gnome with a weird accent was fun. Even writing my silly little backstory was fun ...