This issue was discussed in 2018 in the following thread, which you also started:
https://forum.audiogon.com/discussions/items-for-sale-here-and-on-ebay-without-remotes My comment in that thread:
One reason a seller may not have the remote, at least in the case of an older piece, is that at some point in the past he or she may have left its batteries in too long and they leaked. Which might have created such a mess on the terminals and elsewhere inside that it was thrown out.
Another possibility is that a remote was discarded simply because it no longer worked, and the owner chose not to replace it. Or the receiving transducer or related circuitry in the component no longer worked, and the owner erroneously assumed that the remote itself was at fault.
Although it hasn’t happened to me too often, over the years I have experienced multiple failures of both remotes and the related receiving circuitry in components.
Regards,
-- Al