Even if you honestly wanted to implement this, the real elephant in the room is how to manage multiple jurisdictions. For example, the US government and its contractors routinely use off-the-shelf hardware and software. If China happens to confiscate one such device, would we want to live in a world where they too have exceptional access? If the implementation exists, you're kidding yourself if you think only the US can require it.
Even if you honestly wanted to implement this, the real elephant in the room is how to manage multiple jurisdictions. For example, the US government and its contractors routinely use off-the-shelf hardware and software. If China happens to confiscate one such device, would we want to live in a world where they too have exceptional access? If the implementation exists, you're kidding yourself if you think only the US can require it.