I'd hazard a guess that they want to keep the matrix mixer software and their algorithms as secret as they can because no one else really makes polys with this power and ease of use these days. Maybe thats not the reason but i can't really think of many other reasons why they wouldn't make it open source.
If the current software has already maxed out the resources of the device, what would be served by open-sourcing the code?
I'd guess, instead, that it's being re-purposed somewhere else, in another product....