I really kick myself for not buying one or two when I could. Now they are just in the ridiculous price range ! I also should have bought a couple of M105 trailers too. There even asking to much for those.
I think I paid around $900 for the first M1101 I had back in 2012, and later sold it for $2100, so not bad but like you I thought there was an endless supply.
Then we bought the house and I needed a trailer again. I had my eye on a particular trailer with a generator with the idea to pull the gen off and set it next to the house, and then I'd have a trailer. Lost that auction but there were a dozen M1101 and M1102s available, so I bid near the end when all the big spenders had gotten theirs.
I got one for $750 and sold the two wheels for $400, saved almost $300 in delivery charge when I hauled a yard of gravel. Two trips to Ikea about 50 miles away getting furniture for the house.
It doesn't get much use at the moment but it's paid for and not taking up much room.