If that were the case, I'd expect to see a lot of mid-level and inexpensive gear, the selection of receivers makes it apparent that he knows what he's looking for and only buys what there's money in. There are 100 low-model Technics, Magnavox, Zenith, etc. etc. stereos out there for every big Pioneer SX receiver for example, his selection is skewed. Speculation I agree, but it's hard for me to believe (based on the evidence and his no lowballers attitude) that he hasn't been doing this for a while.
I know people in recycling, and I see what they get in the door, ... I've never asked to buy anything because it is mostly crap. This looks like a collector/flipper to me.