Because:
A) If you want to work with a flat rate agent, go find one. Every property I have in my pipeline right now is on a different commission level, and only a couple of them are this magical "6%" the public loves to believe is "standard". Some of them are even fixed amounts.
B) It's only "6%" if the agent does both sides, otherwise it's whatever the agreed upon split might be - say 50/50, so you are only getting 3%. And, as a few astute observers in this thread have noted, the brokerage is going to further reduce what goes into the pocket of the agent themselves. I've had plenty of deals where my actual net was at or under 1% - I've even had deals where I lost money.
C) So if I sell a $10MM property that takes a year to sell and needs tens of thousands in marketing dollars to sell, I should accept only $10K in compensation?
D) Let's say you've got some shitty dilapidated house or scrub ground with zoning issues, maybe a barely inhabitable cabin somewhere. I find a buyer for it to get the monkey off your back. What's that worth to you, to have the pain gone? You think I don't deserve compensation for spending potentially months or even years to bring you a deal? When I sell properties like that, it is at best a break-even proposition for me, but someone has to step up and assist the public.
E) Everything I listed in my post is about risk management. I am assisting you with not buying a foot gun. In some cases, I am assisting you with buying an asset that will bring cash flow or other financial benefits. In other cases, I may be assisting you with getting a financial drain off your back. Perhaps not for you, but do you begin to see why these service do have value for many consumers?
It's normally about this point that someone in one of these threads says "but I'm taking about 'normal' deals!" Dude - anyone who has been in the real estate business for more than 5 minutes knows that the so-called "normal" deals that the public loves to talk about are maybe one deal a year for an active agent. They are the unicorns of the real estate world. Likewise, people in urban markets have likely no idea the variety of real estate transaction that happen in the world. At the moment I've got transactions in my pipeline for land development, commercial, leases, duplexes, not to mention basic residential work. And every single one of those have unique challenges.