It's astonishing that all communication is not encrypted. If you are sharing information over a common carrier, you should expect that somebody is going to be grabbing and examining the bytes.
So, somehow, it is just not the norm to encrypt communication. One reason might be that during the eighties and nineties as the internet was going wide, ITAR and patents on systems like RSA made people and companies nervous and unwilling to go there; that was definitely a missed opportunity.
Perhaps another problem is that there's no money to be made in encryption; and there are real (small, but real) costs in establishing it.
Why is there no encrypted "WhatsApp"? It would not be hard, it would be trivial to deliver through Google Play, and there would be a immediate market. If the connections were truly peer-to-peer, the infrastructure to support it would be almost zero.
How has the world convinced people not to encrypt all communication?