I think it is also about the fact people already feel their email is secure enough. To get to your email a hacker would already have to break into gmail or your

I think it is also about the fact people already feel their email is secure enough. To get to your email a hacker would already have to break into gmail or your network (or one of the servers your email passes through). Also email has been around a long time, but the main way of getting someones email is still break into someone account by phishing for their passwords. If the attacker logs in to gmail using your own password, encryption is not going to help (assuming you're envisioning a gmail that does automatic encryption of email and must decrypt it when you view your emails in your browser).