The last time I sold a house was 2011, when the housing market was still down from the 2008/09 crash. I talked with multiple agents and never got a sense of them doing much to push the house other than listing it on MLS and coordinating showings. For the seller agent, they didn't even really want to be at the showings -- they'd just provide a lockbox and give the code to the buyer agent. So where is the value there? On a median home sale, the seller side agent/broker is netting $12,400. A lockbox and MLS listing are in the sub-$500 cost range, so where is the additional $12,000 in value?
I at least understand the incentive on the buyer side. A buyer can just ring up an agent and have them do their home search for them and coordinate everything. The buyer doesn't bear the cost at all, so why not utilize that convenience?
Anyway, after talking with a few agents in 2011, I had one recommended to me. He could get deals done quickly and was great to work with, so I was told. I met with him and he wanted to list the house at 8% below the price I thought the house was worth (no bidding wars back then so this was no good) and flat-out refused to reduce the total commission from 6% to 5%.
I said "good riddance" to the agents and did an MLS self-list for like $400. I set the buyer-side commission at 1.5%. I still got plenty of people looking at the house and sold it for the value I initially established it was worth. So I ended up saving over 10% from what the whiz-kid agent would have cost me in lost value and fees.
So back to my original point -- where is that seller value coming from? There isn't much legal stuff the agents help with. You need a purchase contract (boilerplate in most cases), some standard state/federal disclosure forms, and then the title agency handles everything else.