[runako]

> Most of the big tech cos. can replace Zoom overnight.

This ignores the fact that Zoom rose alongside competing offerings from all of the big tech cos. You cite using Google Meet, which has essentially existed (as Hangouts and G+) for all of Zoom's lifetime. Microsoft bought Skype around the time Zoom was founded (edit: and obviously has Teams now). Cisco bought WebEx in 2007. GoToMeeting (Citrix) is older than Zoom.

And that's without counting the transit providers (AT&T, Verizon, Comcast, etc. in the US), who have been doing video chat trials since the late '80s. Again, all big rich companies.

Edit: Amazon has video calling in Alexa & Chime. Facebook has Portal. IBM had Sametime until 2019.

The assumption that the big tech companies can replace Zoom overnight needs to account for the fact that Zoom started in a marketplace crowded by competition from big public companies and should never have achieved traction. Not to compare them directly, but people made similar arguments about Google, which also launched into a crowded marketplace and was "overvalued" etc.

Note: I am not taking a position on Zoom's valuation.