> So is open source actually a core item as the author asserts or just a nice to have?
I think there's a difference in terms here. Having a computer that lasts for 50 years doesn't necessarily mean that you want a computer that is forever unchanging, frozen in amber. You should be able to upgrade a long-term computer, if you want to (including the software); the point is just that you don't have to upgrade.
For the "frozen in amber" use case, sure, you could just pirate the proprietary stuff and hope to fly under the radar. But for the living use case, you need open source, even if that's based on some decompiled proprietary code.
If you want a computing environment that lasts, open source _is_ a core item. Hardware isn't forever and at a certain point will have to change (even chips break/wear out, not to mention capacitors and other bits...)
If you can port your OS and your apps and have control over your data formats, you're in a position to adapt to change.
I think there's a difference in terms here. Having a computer that lasts for 50 years doesn't necessarily mean that you want a computer that is forever unchanging, frozen in amber. You should be able to upgrade a long-term computer, if you want to (including the software); the point is just that you don't have to upgrade.
For the "frozen in amber" use case, sure, you could just pirate the proprietary stuff and hope to fly under the radar. But for the living use case, you need open source, even if that's based on some decompiled proprietary code.