At least from the perspective of the legal profession, the scope of "fiduciary duties" of realtors seems relatively constrained. Buyer's and their agent's interests appear to be misaligned. I can't think of other examples of fiduciaries where, the more the principle pays, the more the agent is compensated, like on the buy side of a standard realtor agreement. Fixed fee or hourly comp. would eliminate the misalignment, but my sense is it's disfavored in the industry.