For example, it could be regulated that if the flip is switched (or a fuse is blown irreversibly) on a device, responsibility for the device and its software fall entirely onto the owner. So if they get phished on an unprotected device and lose their life savings, it's entirely on them. Manufacturers and service providers have no obligation to support them.
I think efuses being blown by device manufacturers should be illegal.
I think bootloaders that don't allow the device owner to run whatever software they want should be illegal.
I think device owners should be permitted to repair their devices without losing functionality because of DRM embedded in the parts themselves.
I think a physical switch, exercisable only with physical access, should be present on locked-down devices to allow the owner to exercise their ownership over the device. If that means that "attestation" functionality breaks and that causes some third-party software to "break" so-be it.
(I think the problem with banks, etc, requiring "trusted" devices is also in the realm of consumer protection, probably in banking regulation. I haven't thought about it deeply.)