Oh I don't know..
Thanks to rapid changes in technology such as rise of Internet it has become easier to market all sorts nowadays. In past you put an advert in local newspaper, sought out a "junk man" or someone who bought second hand appliances.... Now even estate sales (which is where these appliances come from) are online.
Results are rather uneven IMHO. Just as with fleaPay, CL and elsewhere many vintage appliances of all sorts listed on these auction sites don't sell. This meaning failing to attract a single nibble.
If seller of these units and others "knew what they had" so to speak they'd do reserve auctions, which are quite rare on sites like HBid.
There is still plenty of things out there, I mean look at that haul NOS vintage Maytag, SQ and parts auction from WI several months back. Overall believe many are listing such things because they are in search of a market.