Zoom came along with a securre video/voice chat, sure it's American, but it was by far the world leader
Microsoft then used its monopoly in office tools to push Teams to everyone
You can't compete with a trillion dollar company offering your product as a bundle your clients already pay for, even if your product is better. Even VC money runs out eventually
To be fair, Microsoft already had Skype (for Business) and NetMeeting before that. It's not like they were new to that market. NetMeeting existed for more than a decade before Zoom even came into existence.
Zoom had COVID-19 play in it's favor, that's about it.
Zoom has long been the most unsecure video/voice application.
Remember how they installed an open web server on people's computers which could be accessed by anyone through the web?
https://infosecwriteups.com/zoom-zero-day-4-million-webcams-...
Apple had to step in and patch it for them:
https://techcrunch.com/2019/07/10/apple-silent-update-zoom-a...
Or when they sent your chat data to Facebook?
https://www.vice.com/en/article/zoom-ios-app-sends-data-to-f...
How it was discussed on HN: https://news.ycombinator.com/item?id=22703000
Or when Zoom was leaking private information?
https://www.vice.com/en/article/zoom-leaking-email-addresses...
Or do you remember how those geniuses rolled their own crypto?
https://citizenlab.ca/research/move-fast-roll-your-own-crypt...
Or maybe you remember that Zoom has the ability to listen in in real-time on meetings held on their platform?
https://www.bbc.com/news/world-us-canada-55372493