They already have a version of that - it's called Windows S Mode (Windows Store apps only, no EXEs or scripts, Edge only for browsing). If they get away with it, they would make it the default. Required Microsoft accounts was a step in that direction.
It will happen. We've been the frogs boiled in the pot for years, accepting forced attestation. Eventually they'll close off running unsigned code, and the PCs will probably have bootloaders locked to Windows as well, so you can't escape.
It’s sad that smartphones now hold so much personal and private data but aren’t really under the control of their users.