Linux also used to be a "hobby" OS. Now it powers the internet. Things change.

"open source" hardware is never going to work the same way as open source software does. Hardware is fundamentally capital-intensive to produce. Software can be produced (compiled) using hardware that many people have readily available. This is a fundamental, intractable difference.

It's the difference between free knitting patterns and free cardigans.

It took Linux a couple of decades to get to that point. And it had immense business value in having such a massive infrastructure open for everyone.

For hardware our world is not there yet and won't be for quite a forseeable future.