[skeeter2020]

Teams is not free, it's a free addition to the subscriptions that almost every IT department buys already. So you can think of it as a subsidized moat, or a loss-leader for new clients. Any competitor needs to figure out how to cover the not insignificant costs of running this service, plus to give them their due, Microsoft support is better than almost everyone else in the enterprise setting.

[basch]

It's not even free in that it mostly just replaces the Lync/SharePoint interfaces. It's a feature people were sold that was rewritten and replaced, and the old feature removed.