I used to work in the RE business and there are good agents that earn that value and there are bad agents that don't.

You are paying for market expertise, negotiating experience and arms length distance.

On a slightly different note, this podcast and the book "The Middleman Economy" go into detail about why middle men (like real estate agents) are useful: http://www.econtalk.org/archives/2016/03/marina_krakovsk.htm...

Edit: typos