Ed Felton tweeted a few days ago: “Often hear that the reason today’s Internet is not more secure is that the early designers failed to imagine that security could ever matter. That is a myth.”
This is indeed a myth. Much of the current morass can be laid at the feet of the United States government, due to its export regulations around cryptography.
https://gettys.wordpress.com/2018/04/09/mythology-about-security/