Firstly, discord is entirely the wrong medium for documentation.
Secondly, documentation should be at least as accessible as the code. That is to say, if I can view the code without creating an account for some service, then I should also be able to read the documentation too.
I think because such an undertaking would require a wide breadth of extremely specialized knowledge. It would require intense coordination of many experts to work together over many years, all to design something that:
Item 1 is OK for hobbyists, who might value open source over new-ness, but item 2 all but guarantees that only big corporations can actually get involved. They don't care about free and open source. They just want a computing platform that their engineers can develop a product for. As long as there's enough documentation for their goals, open source is irrelevant.
The power of modern computing comes partly in how it enables abstraction. You don't need to understand the physics of electrons through a transistor to write a video game. Overall, the open source community has generally converged on the idea that abstracting away the really hard stuff is an acceptable tradeoff.