The floor at the top end is held up by the cost of the service, not by client generosity. Run the $5M example properly. At 2.5% the buyer side gross is $125,000. At 2.3% it's $115,000, so the observed drift costs $10,000 on that file. Now take the agent's split with the brokerage, call it 70/30 for someone with volume, and you're at $80,500 instead of $87,500. The $7,000 difference is real but it isn't what decides whether the niche works. What decides it is deal count. Six closings a year at that level is a good year, and one buyer going cold in escrow moves annual income more than a 20 basis point fee change ever will.
The listing side is where the percentage compression actually bites, because the luxury listing agent funds the marketing out of the fee. Professional photography, film, staging on a large house, print placement, and a broker event can run into tens of thousands on a single property, spent before any commission exists. Compress the percentage and you haven't compressed the spend.
On the data itself, be careful how much weight it carries. Roughly a dozen states don't make sale prices public, so commission and price studies lean on the markets that do disclose. A national read on luxury fee movement is a read on a subset of luxury markets.
The thing that would genuinely reset the floor isn't buyers negotiating. It's the high end going illiquid. Fee percentage is a slow variable; days on market at $5M and up is a fast one, and it's the one that actually determines whether six closings happen.
