Metadata is incredibly useful in its own right, and spy agencies regularly record huge amounts of data in the hope that they can decrypt it in the future.

Even if you can’t read a single packet, noting a surge in bandwidth utilisation is a signal in and of itself. But you probably can read the headers.

Maybe the NSA can decrypt RSA or Diffie-Hellman. We don’t know. Maybe they save it for when they’ll get the keys. Another way is to saturate so much the network with spy equipment that it’s futile to search and remove it.

Plenty of unencrypted traffic still around - connections between datacentres via dedicated fibers, phone calls, SMS messages, e-mails....

"We kill people based on metadata."

-- Gen. Michael Hayden (retired), former Director of both the CIA and NSA.

"Ssl added and removed here".

Not everyone treats long haul as secure until they learn the hard way. Few are big enough to find out.