It goes well back, before COVID.
I sold a Yaesu VX-170 many years ago. I bought it new for about $125.00. I used it for many years. It had a few scratches, but was generally looked after. Battery was used. I put it on e-Bay, and it sold for somewhere close to $170.00. I have no idea why. You could still buy new ones for the $100-$125 range at the time.
Did the same thing with an Icom 2 meter radio. Bought it for around $150 new. Sold it a few years later for close to $200.
I think people get caught up in the 'wanting to win at any cost' attitude. Or, they just have no idea what they are buying and have no idea that they could get something new for a lower price.
On some older stuff, nostalgia does play in to some level.
But I agree, some of the eBay bidding gets absolutely stupid.