I have extensive experience with Wilson Audio dealers on a daily basis. I work for Wilson Audio.
Multiple dealers who do this exist. It's actually pretty common. As for the time it takes, I am well aware. I have installed the diodes on numerous speakers, at home and in the field. As long as the comparison is for actual purchase consideration and not just a desire to "hear the difference," the time is well spent by the dealer. Given how many new Wilsons below AlexxV are being ordered with Acoustic Diodes, it is safe to suggest that someone is listening.
At this point, WAMM, XVX, and AlexxV are delivered with the Acoustic Diode. Given Wilson's predilection for carrying technology forward into new designs, it's a safe bet that future Wilson speakers may well include Acoustic Diodes.