> How is this not a solved problem?
It's not because the big 3 (Apple, Google and Microsoft) do not want you to encrypt your email, so they can use it for data mining. If 70% of their gmail users used encryption, I'm sure they'd be turning the service subscription only or (as it's customary for G) shut it down.
So, if you need encryption you have use an external "add-on".
The problem of secure email is solved, it's just not pushed as a standard because:
a) Users don't understand they're being tracked (or don't care)
b) It's not promoted (actually it's being demoted) by industry leaders
The fact that H. Clinton and her equip didn't use GPG is appalling, doesn't make sense. This group of people had big stakes on the privacy of their communications, they went as far as setting up a mail server and forgot to apply encryption? I just don't get it.