Why can't Johnny read a privacy policy? It's because privacy policies aren't being written for Johnny to read. They're being written for regulators and lawyers to read. Or well, more fairly, they're being written for Johnny, in the ways that regulators and lawyers think they should be written.
Today, privacy policies are being written to try to do two contradictory things. Like most things in life, if you try to do two contradictory things at the same time, you end up doing neither well. Here's the contradiction: should a privacy policy be a short, simple, readable notice that the average end-user could understand? Or should it be a long, detailed, legalistic disclosure document written for regulators? Since average users and expert regulators have different expectations about what should be disclosed, the privacy policies in use today largely disappoint both groups.
On the one hand, privacy policies are supposed to be disclosure documents for the average end user. In other words, privacy policies are supposed to be simple, readable notices that are used by any entity that processes personal data to tell their users basic stuff, like what data they collect, how they use that data, whether they transfer that data to any third parties, etc. In addition, privacy policies are the main mechanism for entities to obtain consent from end users to process their data, even if that consent is often implicit.
On the other hand, regulators around the world, with good intentions, continually call for longer and longer privacy policies (not in those words, of course), by demanding that X, Y, and Z be disclosed. Whether Johnny cares about X, Y, and Z is irrelevant. Companies have to disclose X, Y, and Z, or they'll risk regulatory sanctions. Johnny probably couldn't understand X, Y, and Z anyway, and X, Y, and Z are probably privacy-legal terms of art. HIPPA is a famous example of legally-required privacy notices that Johnny can't read.
The time has come for a global reflection on what, exactly, a privacy policy should look like. Today, there is no consensus. I don't just mean consensus amongst regulators and lawyers. My suggestion would be to start by doing some serious user-research, and actually ask Johnny and Jean and Johann.