Email an open standard? Sure, on the surface it is. Running your own mail server and getting your emails delivered to gmail/outlook users? Good luck.

Who cares what the form is, if the substance is the problem?

Same with web. To this day, nobody besides google has the possibility to compete in the browser space. So much shit was added to the web standards, that you need an incredible amount of resources to produce a modern browser engine (I am talking one that users can use for their daily stuff, not lynx). You have chrome, you have all the chromium clones, you have Firefox which is anyway paid by google, and you have safari. Period.