It's just not an easy task. I can't help but compare it to the Nouveau project spending years of effort to reverse-engineer just a few GPU designs. Then Nvidia changed their software and hardware architecture, and things went from "relatively hopeful" to "there is no chance" overnight.
I agree, it's a lot of work, plus Apple definitely is not not going to help with the project. Maybe an alternative is something like Framework -- find some good enough hardware and support it.
