Why is the Shelter 501 mono so expensive?


Rainy day and I am chilling listening to records. I have a shelter 501mkII, my second, and I've listened to a few mono pressings that I really enjoy. I am wondering about a mono cartridge. In looking into this the Shelter 501 mono is almost twice the price of the similar stereo cart. Other than units sold I can't imagine that there is a lot of difference between the two. Any thoughts?
128x128davt
Thanks for all of the input. I do have some old mono blue notes and others as well as some older rock in mono and am surprised how much I enjoy them, even with my stereo cart. I am going to try and find a mono system to listen to a few of these.
It has nothing to do with "Supply & Demand"
Before Axiss had it, the price for it was 500,--$
(that was at the time when I listened to it)
Perhaps they are just opportunists. Most carts are not expensive to make, although one would think so with their outrageous pricetags ! Remember good old Barnum, everyday they can run with the importers to the bank ! Suckers born to know it.
To think one pays 500 to 10,000.00 unbelieveable and to think I paid thousands for a Koetsu years ago, sure returned that one in a hurry !