Why is the SD1 Merrill So Expensive?

Years ago the SD1 Merrill was selling for hundreds less than it is today. Does anyone have any idea why this is?

https://www.sigmaphoto.com/cameras/dslr

https://www.bhphotovideo.com/c/product/846208-REG/Sigma_C26900_SD1_Merrill_Digital_SLR.html

The B&H price is for special orders only, for some reason. I guess they aren't selling enough of them.

On another note, it looks like Adorama is clearing their stock of them, with an $800 instant rebate):

https://www.adorama.com/sgsd1m.html

My own theory is that Sigma wants to keep a DSLR available for as long as possible, so they can claim to have three interchangeable lens cameras in their line-up. I think they should make a new version of the SD1 Merrill, like the SD1x Merrill. It could have twice the buffer memory, a better review screen (at least 1 million pixels instead of 460,000), a faster processor, which would let the camera operate faster in so many ways (including clearing the buffer much faster), and they could use the exact same body and batteries, allowing current owners of the SD1 Merrill to upgrade, taking their batteries, battery grip, etc. along with them. They could add in-camera DNG recording to the SD1, and they might even be able to add live-view to the camera. I believe a lot of photographers would buy such a camera, not only because it is faster than even the SD Quattro H, but because many photographers prefer an optical viewfinder. Sigma could make the camera for $2,199 and continue to sell the SD1 Merrill for $1,799 (the retail price over a year ago). That would give them two DSLR cameras that they could be selling. Then they could make an SD1x Quattro. Wouldn't THAT be nice?