There was a notion awhile back that leaving out FA information was supposed to cut down on the egoish names-in-the-guidebook syndrome, but it was a silly idea. That info is important historically, and it can provide valuable insight into a route as well. Take City of Rocks for instance, knowing who put it up will give you some clues as to how clean something may be and how thoughtful fixed pro placements may be. In Red Rocks, if Joe Herbst was on the FA, you'll know you'll want to bring your "A" game to that 5.9.
I wrote a guide way way back in the day, it was a fair bit of work, sort of full time for 3 months, but hey, I got college credit for it and made up a bunch of names that are still in use 34 years later. Takes chutzpah to write a guidebook.