This is, at least in part, a result of MINIX using a highly permissive license. It’s easier to use an open source OS in relative secrecy if you aren’t required to release your modifications. And an organization with deep technical expertise like Intel would not likely need much assistance from the community for their implementation.
> This is, at least in part, a result of MINIX using a highly permissive license.
Not at all. MINIX was actually Intel's second choice, they tried first to fit Linux into their new x86 based ME. But the maintainers were uncooperative:
And this shows that the license really isn't that critical. Vendors don't like to maintain operating systems, so they have a vested interest in upstreaming their modifications. Why maintain something yourself if you can get someone else to do it?
BSD licensed projects see plenty of contributions, they're just not as popular as Linux because of historical reasons. I and most BSD fans blame the AT&T lawsuit for BSD losing popularity and Linux gaining popularity. That being said, BSD is still quite popular, though somewhat niche.
Companies not upstreaming code will happen regardless of the license. Plenty of companies maintain Linux change sets because they're not obligated to release them, but plenty more upstream their changes when not strictly necessary. It just depends on the value proposition of releasing improvements.
They could still require redistributions to include a copyright notice. I think the real issue is that Intel might engage in product binning without changing the source code.
I'm pretty they just forgot. MINIX is under a license that does actually still require a copyright notice, and I'm pretty sure that after the news came out about it being used, they went and fixed the fact that they'd apparently forgotten to include it.
I know they at least formally requested some changes, but I don't know if that means they contributed. I'm guessing they didn't want the public to know they were using it, likely because of the nature of IME.
I'm still looking forward to the day when someone figures out how to install X11 on Intel ME, thus ushering in the Year of the MINIX Desktop rather instantaneously.