So what is going to be the unrestricted device? Looks like it won't running on Windows or MacOS which are going very quickly the locked down route. I would be happy if there was a good alternative.
The big fear shouldn't be that you won't have anything to run so much as the idea that popular general Operating Systems in the future will integrate too many advanced features and introduce hurdles to general interoperability that makes it harder for open source alternatives to be useful.
So far it hasn't been too big of a problem, but if operating systems start being augmented by substantial amounts of AI or machine learning derived efficiency improvements upstarts might have trouble keeping up, but I wouldn't count out the creativity of the Open Source community to address these issues.