It really isn't helping.

I have been in the art market for several years in many different positions.  I have represented artists, I have worked in galleries and I now sell my art.  I have seen artists pay from 15-60% commission and I have seen collectors think it is highway robbery.  Galleries are storefronts that you aren't dealing with the business headaches to be in.  There is rent, taxes, marketing, event planning, insurance for the store, shipping and inventory.  They pay their representatives, have active mailing lists, managers, accountants and lawyers and depending on where their store front is, city district membership fees that can be incredibly high.  All of this can create an overhead that makes it challenging to stay in business.  The last thing a gallery wants to hear is a client saying to a visiting artist, "Call me when the show comes down and we can arrange shipping."

You collector might think they are helping you, but they are actually running the risk of putting you on a black ball list that will keep you out of that gallery and possibly others.  Recently I heard of an artist scolding a gallery for wanting a 40% commission.  The director was pretty calm for being told that they were greedy.  I don't know who the artist was but I wasn't impressed with them.  My first thought was that they weren't a real professional.  If they were, they would know that 40% is a moderate commission.  There is a gallery in Idaho that was demanding 55% and didn't even have a website.  They were relying on the fact that they were on the main drag in this little tourist destination.  For 55%, I want to see the artists represented on the website, hard copy advertising and a social media presence.  Galleries in historically busy tourist destinations that are busy year round ask 60% but that is in the Hawiian Islands.  Not a town that is busy for 3 months in the summer and 4 months in the winter.  One of their competitors asks 50% but is nationally recognized, and advertises regularly.

If you don't like the commission, don't sign.  If you are pleased, make sure that your clients know that you are pleased to pay the commission.  The gallery owners will appreciate your vocal support and the education to your and other collectors.  You are educating everyone when you speak out loud so consider what you and your clients are heard saying.  As for me, if a gallery is a consistent seller of my work, I'll pay; gladly.