Requires designers. Both hardware and software. Those sorts of people can command high price if you want the job done properly. I know you say "no software interface required", but if you're already going to put it in a desktop product, then it wouldn't really make much sense to do so otherwise since MiniDSP can offer this as is. You actually want an intuitive or capable system like the way RME handles it, all in-box, and all accessible with a proper interface. Whether that be a touch-screen or just hardware buttons to the side of the screen is not paramount, but having one or the other would be.
The other issue is, if this is a desktop product, you have access to a desktop, so most makers won't bother seeing as most folks can do it on their computers anyway.
In case you haven't noticed, audio companies don't really care much about things other than looks and only recently, performance. There's lots of money to be made with simple boxes (which is why DACAMP combo boxes aren't too common either compared to separates). Anything with many features and you (potentially as a Asian manufacturer) run the risk of having your product come really close to the cost of things like the RME DAC. So unless you thoroughly beat their implementation, good luck with competing with a Made in Germany label. And to be frank, software consistency and quality outside of the US and EU isn't so great.
Also at the pace which some of these desktop products release, they're not meant to have staying power on the market since their design is due to be replaced soon anyway, if you have to take into account new hardware and making sure it functions properly for every iteration, I imagine R&D costs keep becoming a problem when you want to carry all that functionality over to the newer iteration without it being bug ridden. Matrix Audio, for all the praise I give them in terms of build quality, you can see on threads dedicated to there devices on this forum, constant reports of software issues and quirks. This is the sort of thing you invite once you want to start producing something with more features in the box beyond audio specs.