I'm an agent and investor and one of the reasons I got into the business was because after working with an agent on my first deal, I was left thinking "wow, I could definitely provide better service than that guy". As I see it, the role of the agent is essentially one of service, consulting, and marketing. We need to make ourselves available to conduct showings, hold in-person and phone meetings, write contracts, coordinate inspectors, appraisers, attorneys, etc, negotiate contracts and pricing, coach people on the process and do what we can to present the home in a way - whether in photos and in-person - so that it will sell in a reasonable amount of time at a fair price.
You sound like you are a pretty DIY type of guy, and I can resonate with that, but there are plenty of people who are not. Some people really do not understand the market and could get taken advantage of. A lot of people become emotional or unreasonable during the transaction process (you wouldn't believe how many times I have to talk people off a ledge over little things). It helps to have a trusted voice there to tell you that you are not getting screwed over. There is also a lot of risk in the job as an agent, we often work with clients for months who ultimately decide against buying or selling and we never get paid anything. For each transaction that is successful, there are one or two that die on the operating table.
Side note, I think talking about the "average broker" is a bit misleading because I tend to see extremes more frequently than the average. You have your part-time agents and new licensees who might only sell a few houses in a year. Then you have your top producers who have been in the business for many years and conduct 10x the business of the "average agent".
I think the business has changed and there is pushback against the traditional commission structure, and I think that's healthy. I would agree that when I am buying or selling a 250k home at 2.5% there is little room for me to negotiate my fee, but with more expensive homes we as agents need to work harder to justify our value.