I think the reason we see a lot more generic listings these days is because EBay has created listing functions that encourage it. I’ve recently been selling one or two items per week. (self induced purge). EBay now gives me the option to pick from and copy any other listing that EBay determines may be similar to the item I’m selling. They didn’t have that previously. I always had to make every listing from scratch. But now EBay gives me a few different listed items to pick from, with the explicit recommendation to copy it. I even get suggestions for what to call it based on the few words I provided. This opens up the flood gates for people to cherry pick from high dollar goods and proclaim they have the same thing for sale. They also tell me what to ask for it, which, has been generally accurate in most categories. But only because I actually know what I’m selling. Many don’t know. They just sell whatever comes in the door, for however much they can get, with EBay “assisting” them to list their items efficiently.
As for the topic at hand: I’m not surprised by the listing. Even less so after reading the sellers response to you. While you did make a statement with your offer, any decent vendor would have declined to engage you further. Low ball offers are expected, even on actual items of value. Hope springs eternal, y’know.