Cundco is essentially Hans im Glueck's shop. I'm not precisely sure of the legal connection between them, if they are HiG or a subsidiary. As I've said before, HiG has to print things on an industrial scale. I'm sure they'd like to know precisely how many copies of an expansion they would ever need, but have to make an estimate and determine the speed at which they'd like a return on their investment. I'm sure HiG can estimate these things very accurately; though I am sure it is very difficult to estimate. Do you print an infinite number of copies of something because we'll still be playing Carcassonne in the year 3100? I doubt the colours will match, if they decide is it time for a new print run. I suspect the die-cutter will have been replaced a couple of times too.
You also have to remember that online forums are a bit like an echo chamber, collecting like minded thoughts.
Everyone doesn't want Crop Circles (because Crop Circles II was a far better expansions) and
everyone doesn't want Besiegers, because it was sold as an exclusive-deal to an online retailer and only went out of stock in Easter 2016. Before that date it was readily available, there was a good 2 year window to buy a copy, which is more than most boardgames! Japanese Monasteries was a similar deal for the Japanese Publishers (Moebius). I imagine Cundco negotiated a deal to accept some copies of the print run, while others were shipped to Japan to be included in their copy of the base game. The first time the 2.0 artwork was released in Japan. This was only made available in October 2016, this will be why many copies are available.
Who knows, in a couple of years they
may find another cellar full of copies of all of these expansions!