Earlier quoted context omitted.
Do you think no one has fixed email because the problem is too hard, or because there is a lack of creative/ambitious founders?
The main reason is that you need to be backward compatible with 30 years of terrible hacks. That's why there's a ton of vaporware email clients --- there's a huge amount of work that most of your users don't suspect. Full-disclosure: I work at a company building an open source email client ( https://nylas.com/N1 ) and an API to simplify email ( https://nylas.com/docs )
Little question: do you plan to support PGP?