> No one wants to buy the actual chat application itself, because they could build equivalent technology on their own.

Surprisingly, they didn’t. I am using Microsoft Teams for work daily, and that is the buggiest and the most poorly designed application I have ever used, not to mention their awful macOS integration or how they synchronise notification statuses between devices.

I read somewhere that the Teams concept came out of a hackathon where someone integrated skype with sharepoint. It still feels like it is a proof-of-concept rather than a production ready application.