Both enjoyed mass adoption without needing billions in VC funding and PR.

no one uses Skype anymore though

He left out the /s

While it might be (way) less popular, Skype still exists. [1]

Also:

> Microsoft Teams is based on a number of Microsoft-specific protocols.[50] Video conferences are realized over the protocol MNP24, known from the Skype consumer version. [2]

[1] https://www.skype.com

[2] https://en.wikipedia.org/wiki/Microsoft_Teams#Protocols