Many attempts to replace email were made, but email is here to stay.
Email works, but CODING EMAILS IS HELL! Email clients support a subset of undocumented HTML with many quirks and a 1998 feeling to it. Companies spend money and time on writing these. This has got to change.
The only companies that can change this are Google, Apple, Microsoft and Yahoo. Not just one of them, but all of them together.
They hold the most useful email clients (gmail, outlook and apple's iPhone client, yahoo mail). Releasing fixes for ALL past clients that includes a modern browser for showing the emails will solve a lot of pains. There won't be breaking changes if we use the HTML5 doc type. Emails can become amazing and evolve, just like the web did.
Let's make emails great again!