It is difficult to cut out the agent if you are not already living in Spain. Most of the se vende signs are actually an agent when you call, as are the ones on fotocasa. Many that are trying to sell privately are often not physically in Spain, others only speak spanish.
As someone said cutting out the agent doesn’t always equate with paying a lower price.
What does need clarifying is who is the agent working for…buyer or seller. Obviously it should be the seller if paying the commission but when we have sold it sometimes seems a bit muddied with the agent seemingly taking the buyers side in negotiations. I prefer the USA system.