Edit: Child comment has the video. Starting at 20:17, "We wanted to open source the system. So why didn't we? What was the problem? Well, the problem was that it's a deeply proprietary system."
And we're "just" a language runtime and a shell shipped in the OS. I can't imagine how hard it would be to unwind the proprietary bits of something like a GPU architecture running in a tightly integrated SoC with multiple vendors who are all deeply protective of their IP.
I say this all as someone who has been a proponent of open source for 15 years. And all the work was absolutely worth it, and deeply rewarding from a personal perspective.
But I can't say it would probably make the same sense for Nintendo to go through that effort with Pokemon or the N64 architecture.
I don't have time to rewatch it now but I believe the point of the talk was to promote Illumos as the true community-driven open-source fork after Oracle dropped the ball. This is exactly what I'm talking about: the community is often happy to pick up the slack and cover for the failures of these companies, but only when given the opportunity. Yes it's a lot of work, a lot of conversations and a lot of corporate politicking. But how can anyone get started when the relevant parties are not willing to even present an opportunity?
The hubris of those who believe other people should be forced to release their (not already subject to a copyleft license) work is the very antithesis of FOSS principles.
Now if this isn't actually the case and they're just using it as an excuse because they don't want to release it, and they want to continue playing this cat-and-mouse game with leakers and ROM sites forever, that's fine too, it's a little disappointing, but my intention is to present the idea that there is a different way.