I was thinking the other day that a lot of the appeal PA offers is emotional. Think of the great "community feeling" they all have on the PAMB - as far as I know, real publishers don't have any thing of this sort. I hardly know any other writer with my publisher: I met one lady at a party, and that's it! I wouldn't think of hob-nobbing with other authors of my publisher, simply because we share a publisher. I have several writer friends, but it just so happens that we all have different publishers.
PA-lers have a distinctive PA feeling. On the message boards I saw a post of someone wondering if they should all send their books to celebrities. There is a fuzzy, touchy-feely "we" atmosphere there, a think-alike solidarity.
I think that the PAMB is an extremely strong marketing tool for just this reason. It generates a feeling of belonging in readers, people who perhaps are lonely and struggling with private issues, people with low self-esteem. There, they see al these authors getting all euphoric; a huge balloon labelled "success" drifts in over the horizon, their spirits lift: I can make it too! I can be a part of that! I want to belong got the club! They are all so happy together! Let me in!
The "New authors arrival" thread has a particularly rose-tinted edge to it. "Here we are! We're in the door! Give us a hug! We're part of you now!" "Oh, welcome, welcome to the family! Hugs and kisses, isn't it a great feeling!"
Nothing wrong with all of this, of course; but I do feel that PA manipulates this human need for belonging in order to make money. Of course, lots of other companies do that. All those dating agencies, for example. But here, the banner of fame and fortune goes before...