I'm a little jaded on the real estate agent model in general. It requires one person to be a jack of all trades and frequently results in them being a master of none. I'm especially salty because we live in San Jose and agents get obscenely huge paychecks for selling single homes, and they still manage to be ignorant of vital pieces of information. (In one case, my new neighbors were surprised when the giant pine tree in their back yard died and had to be removed at a huge expense; if their real estate agent had actually "known the neighborhood" he would have known that every single pine tree in the area is dying from pests and this is an expected expense.)
When we bought, we used Redfin, which makes a lot more sense as a system. It works more like an actual office than a bunch of lone wolf agents. A separate person takes people around for home viewings. The agent is a dedicated negotiator and handles the final part of the transaction. We never met him in person and never needed to; other office people handled the details. The agent doesn't have to do his own marketing or website or anything else.
Now, about your second point, yes, agent dealing, protectionism, and sleazy backroom deals are to be expected, and might figure into your math. (We had one listing agent tell us outright that since we were with Redfin, he'd put an offer from us at the bottom of the pile.) It really does come down to your area, and local forums might be a better place to ask this question than a big international board like this.