There is a food chain when buying audio gear.
I have purchased high quality amplifiers and preamps on here but I had to wait years for the model I wanted. I have dealt with wealthy individuals. I do not believe they put expensive gear on a shelf and do not sell. They put their orders in for something even more expensive and sell the older expensive gear when they no longer use it.
I got my speakers from a guy who was turning his large garage into a listening room. He needed much bigger speakers. Since I live in modestly sized spaces, I was happy to take them off of his hands.
Be aware that any high quality amp or preamp is going to have been manufactured in limited quantities. Buying this kind of audio gear is not like buying iPhones.
Why isn't better quality used gear being made available?
I've been scanning used gear for a while trying to look for an amplifier and a line stage pre-amplifier. To me it seems like quality higher end gear being made available is Limited. Maybe it's a good thing that all this quality gear I'm looking for doesn't want to be sold .
I have never been able to find used cables that are what I'm looking for from transparent, cardas, ect, or other worthwhile brands in the mid to upper price ranges. I guess people keep their old used cables in a box and don't even bother selling them . Maybe it follows that Quality used components sit on a shelf in someone's basement not being sold. It's tough giving up quality audio components even if you don't plan to use them and maybe keeping them around as back up or for a third listening room that never happens.