There's also a reason ipsec is in the ipv6 spec; and a reason Google (reportedly) turned on encryption/vpn of their dark fiber links after the Snowden relevatio

There's also a reason ipsec is in the ipv6 spec; and a reason Google (reportedly) turned on encryption/vpn of their dark fiber links after the Snowden relevations: there is no such thing as a "secure" cable, or "physically private" network. You either encrypt your traffic, or you're vulnerable. That doesn't mean a vpn is sufficient for security, just means it's a prerequisite. People are pushing towards securing transport at the protocol layer - but it leaves issues like unencrypted dns, icmp etc.