It's really a system. So let's say he buys GXR M, he'll have to consider buying M mount lenses, and they aren't exactly peanuts. For the layman, most will consider auto focus cams and the more mainstream offerings from Canikon. So if I want to buy 1 (even 2nd hand), I will be thinking what I am signing up for.
Those who had the M9 and M8, it's a viable backup in case they have to send their RF cams to solms ... but hey, they may also be using the m3s,m6s,m7s,MP, so this GXR option isn't really a like for like alternative (RF), not the same feel of an RF camera.
So yes, I think after the novelty of owning 1 dies down, there's bound to be sellers there to recoup as much as possible even if it means 950 (from 1.4k?).