Comment by jandrese
The 90s had the opportunity to deploy something like PGP widely, but because there was no perfectly safe way to distribute the keys it never went anywhere. The most practical solution the crypto nerds could accept was the web of trust, where you were supposed to physically meet everyone you wanted to communicate with so you could physically exchange the keys, which was never going to scale.
Email to this day is unencrypted at rest and completely transparent to whomever is running your mail server. You don't think Google runs GMail out of the goodness of their heart do you?
There is S/MIME, but probably biggest thing that stopped its adoption was popularity of web mail (so yes, Google and others).