"El reg comments for years have been suspicious that "SaaS" meant software as rental. i.e. that ultimately we'd have to pay annually for our Windows to keep working fully."
That might be why it is becoming more and more difficult to install Windows 10 with a local account instead of a Microsoft account (hint: make sure the PC does not have an Internet connection during the install).
After MS make it almost impossible to install W10 without a Microsoft account (they will then claim no-one uses local accounts anymore, of course) the next step will be to introduce monthly or yearly fees - with the added 'convenience' of being able to set up direct payments to them through your MS account, naturally.