My hope is that it would be an open and free standard instead of some of the usual bullshit vendor lock in

When has that ever happened?

That's an extremely broad question. Are you asking specifically about email replacements, communication standards, or just proprietary software in general?

When has ever a “tech industry’s ‘reenvisioning’ of a free/cheap older, but universal, standard” resulted in “an open and free standard” and not “the usual bullshit vendor lock in”?

Never that I can think of, which is why I stated my hope that it wouldn't be like that. But maybe that just means we can't necessarily depend on a profit motivated corporation to do the 'reenvisioning'

Bingo. See also the rumored “definition of insanity”; i.e. doing the same thing over and over again, but expecting a different result.

Basically anything? When was the last time something like email happened? And it wasn't a giant tech company that created that either.

Maybe something like Webrtc?