OK, let's assume it could be done
If such a system were devised and mandated for appliances on sale in the US, UK or wherever what good would it do? The complaints tell us that there are unbreakable cyphers already out there. So if I were a criminal wanting to communicate with my organisation what would I do?
1. Rent a server somewhere out of reach.
2. One of the unbreakable cyphers to encrypt the message with a suitable key (see below).
3. Wrap the encrypted message up as data within a decryption program to make a file which will self-decrypt once supplied with the key (cf self-unzipping files) and post to the server. For extra points make the file install a selection of nasty malware if supplied with the wrong key.
4. Organisation members download, supply they key, read the message & then delete.
5. The key would be some innocent looking message gleaned from the net by some agreed method. For instance if the intended recipient were a British Muslim of Pakistani origin the key might be taken from a forum specialising in Pakistani cricket. The sender would select some suitably long post, find a comment to it and post a reply under an agreed handle. The key wouldn't be anything the sender wrote but a perfectly innocent message some distance removed. If the recipient were in IT the key could be the first page of Dabbsie's weekly offering.
The recipients would need to exercise some communications discipline, downloading from open wifi, downloading key & message from separate access points etc.
Maybe the scheme is already in use with amanfrommars's posts as they key. It would explain a lot.
The significant point is that encryption technology is generally available. Constraining commercial products to use something broken doesn't inhibit its use by those who want to be secure. Making its use illegal would have no effect. If you're already doing illegal things are you really going to be put off by having your communication channels made illegal? The only people who will be affected are the innocent users of commercial products who will have their privacy invaded.