I get a few of these a year at work and since we're a business we're kind of obliged to keep going with these in the name of customer support service, but it becomes almost a morbid fascination to see how far they're going to go on for.
I had two at the same time going during the spring lockdown, I was kind of racing them against each other to see who'd go on longest.
I don't think it was a scam; before I came to leave in the USA, and before taxes too, I used some of my US based colleagues to purchase eBay stuff that would only ship domestically.
My colleagues would then carry the item with them back to work, overseas, to me.
However, I would always pay them ahead of them closing the transaction; but as I said, we were colleagues, not friends, but happy to help each others.
Reading the transcript, it sounds like the guy that wanted to purchase the S-Trem did not have a good organization in place ahead of time, or did not have people who trusted him to pay them back.
Obviously, if you have not lived abroad, you are not privy of the difficulty to purchase stuff that is sometimes only found in the USA, and sellers not interested to deal with offshore buyers.