I’m not sure. I think the market for film scanners is limited in general. I’ve found that there are a ton of peripheral issues involved with high-quality film digitizing. The harder it is to master, the fewer people who will try it.
I also think that film scanning is a difficult problem to solve as evidenced by all the activity on the Kinograph forum. To put it bluntly, $40K for a mid-level scanner like the HDS+ is a lot of money for most people. Not only that, Filmfabriek is a small company of 5 to 10 people (as far as I can tell). Low-volume market, high priced item, small company with limited marketing budget. I’m guessing those are all reasons that the HDS+ is not as well known. But it’s a really nice scanner. If you don’t want to build one yourself, the HDS+ is a solid mid-tier product.