Earlier quoted context omitted.
It already exists. Use PGP, send messages through anonymous remailers. If you cannot use anonymous remailers, post messages to Usenet in alt.anonymous.messages using Tor. If not Tor, then via a proxy server. If none of the above, just make sure you are not doing it from your house. If even that is impossible, know that traffic analysis will be possible. Why is this something that needs to be repeated to the technical…
The measures you describe are not exactly trivial.
For what it's worth, it is not hard to encrypt a message and post it to Usenet. It is imperfect and vulnerable to traffic analysis, but it is not hard. It is even easier to just send encrypted emails and not bother with anonymity. I have personally seen non-technical people using PGP or S/MIME without assistance.