If "historical inertia" is the only thing keeping macOS a general purpose computing platform, that is extremely troubling. Because it means Apple will not hesitate to lock it down in the future if it's able (e.g. through subversion of notarization).

To me, this is one of the main reasons to fight for an open iOS: if people get accustomed to corporations revoking access to their software for arbitrary reasons, and if the technology exists allowing them to easily do so, then the gradual introduction of these measures to PC platforms will be met with a collective shrug.