At the risk of running the "partially correct" into the ground, I think that the conversion from Chromebook to "no longer a Chromebook but a poorly-specced Linu

At the risk of running the "partially correct" into the ground, I think that the conversion from Chromebook to "no longer a Chromebook but a poorly-specced Linux laptop" to still be "partially correct." It requires firmware configuration changes which may require some sort of jailbreak (per the article you linked)…and iOS devices have jailbreaks available, too, which allows the installation of other software. Many things are possible for a suitably motivated person. But such things are unlikely to be done by your average device user (of any sort), because they don't have such motivation and can't even conceive of why they would bother.