Got millions?
(I was at Symbian when much of that was open sourced: a paralysingly large effort that still left a lot of critical components closed)
Irix did a lot of things in-house and the value of the OS is not generally in commonly available components. I suspect that any 16-25 year-old 3rd-party components that are of any value have modern equivalents which are open-source and probably better in most ways. I would think there is a way of putting the burden of sorting through these issues onto the non-profit receiving the rights much as the burden was passed to HP through an acquisition in the first place.
I'd have less faith in corporations to do the right thing. As an Indian, I get nothing but slave treatment even in America because I'm expected to work for less and harder than my white counterparts.