The tweet you linked is newer than this discussion. And it's also misleading. The major players in the business world aren't E2EE today, so Zoom is breaking ground in that way, but as far as free offerings go FaceTime is E2EE and that's certainly not a niche service. WhatsApp is also E2EE. And there's a platform called Wire which I'm not particular familiar with but claims to be E2EE. And it's also a paid service, which suggests it's targeting businesses. I guess it just doesn't count as a "major player".
