I wonder at times whether this is their game, hoping people will just tell them not to bother sending it back and they get a refund anyway.
As for ebay, I stopped selling anything on there years ago, well over a decade, when someone tried to scam me out of a laptop but failed. If something is valuable enough for me to sell, I sure as shit am not selling it on eBay.
More often than not, I give away my valuable tech that I'm done with, because I'd rather get nothing for it, and give it to someone who'll appreciate it than risk being scammed by some scumbag.
This way, friends and family get my hand-me-down PCs, laptops, phones, etc for nothing and they're still, by the time I'm done with them far better than something they'd buy with their budgets. When I buy something, I factor its lifetime in my possession into it's cost, I effectively expect £0 value left in it when I'm done or I don't buy it; everybody wins.
For old computer stuff, I gave away quite some stuff to people driving to Ukraine. This then goes to kids or their cause.
Probably indicative of not having a very good business brain. However, it always seems strange to me when when people buy things and keep track of their used values the whole time they own it - expecting at some point to trade it in.
A couple of days later I saw the same item relisted. I wouldn't be surprised if the person I was bidding against was just there to pump the price for the seller, or was an alt account of the seller. Obviously against eBay's TOS but I'd be surprised if it didn't happen.
Each of those three claims to be the largest one in some metric.