Even MS hasn't dared to release a version of Windows you can't switch out of "S mode" yet, but the fact that it even exists would be troubling for them.

MS would love a walled garden like Apple have made, but there's no way in hell it would ever pan out for them, and certainly not before regulation arrives (probably from the EU) that would stamp it out, and that's before you take into account the business implications. Windows only exists because of all the pre-existing software. Flattening the only reason to stay would be suicide.