> For whatever reason, distro maintainers working for free seem a lot more competent with security than billion dollar hardware vendors

I don't believe that these billion dollar hardware vendors are really incompetent with security. It's rather that the distro maintainers do care quite a bit about security, while for these hardware vendors consider these security concerns to be of much smaller importance; for their business it is likely much more important to bring the next hardware generation to the market as fast as possible.

In other words: distro maintainers and hardware vendors are simply interested in very different things and thus prioritize things very differently.

Sure. New sales means new revenue. Maintenance and support is just overhead.

It's shortsighted, but modern capitalism is more shortsighted than Mr. Magoo.