alt Hacker NewsTo 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.
Skype for Business is the VoIP component for Teams, now. Sharepoint is the file service for Teams, too.
Basically, Teams is a front end for a bunch of old Mircosoft cloud services... plus chat. Actually more than one chat as teams channels chat is a separate tech stack from private chat. It used to be much more monlothic and then the Sharepoint people got their hooks into it.