They've got CIOs utterly snowed, which is honestly a huge indictment of CIOs, including and especially those in "government" roles.
https://community.zoom.com/t5/Meetings/Why-is-the-Zoom-app-l...
Everyone else seems to be betting the farm on webrtc and web browsers. But video meetings in chrome or Firefox don’t look or sound as good as zoom does. And Google Meet and the rest are at the mercy of web standards. Its much easier for zoom to add features to their product because they’re in control of the entire stack.
I hope the situation changes, but I think it’ll be several years before browsers are able to meaningfully catch up to where zoom is today.
The principal architects and security team don't care that Teams is neither good nor secure. They just know that they can blame Microsoft if things go wrong. Slack was too startupy. God forbid people just start texting each other, or even worse, use Discord.
(Before you say, "But...", PAs don't care if Slack is owned by Salesforce now. SF is just some weird tool that Sales requires and won't stop screaming about.)
So, they already use MS for Office, file shares, Exchange, etc, why not just throw another piece of MS crap into the ecosystem? Who cares if it sucks? Who cares if it was a hastily thrown together piece of garbage that MS scrambled to make when they suddenly realized Slack was beating the snot out of them? They don't have to do any work because they're already in bed with MS.