Maybe in 2020. Teams is the defacto IM app for enterprise now. It may not be to your liking, but most workplaces don't need apps to constantly be adding new features. They need videoconferencing, chat, meeting recording and AI transcription and note-taking. All synced with everyone's Outlook calendars and authenticated by the same SSO used org-wide. Teams has had all of those for years.
For the 1000+ headcount companies who sit outside the Silicon Valley webdev/software dev world, it doesn't. Silicon Valley looks at these as "products". Purchasing managers see these as "commodities" that need to be interoperable with the rest of their stack first.
That's fair, in my last org we used Teams for meetings despite Slack for general chat etc.
Partly I'd say that's due to MS giving it subpar experience in O365 calendar/mail/outlook - you can't join a call directly, best you can really do is link to the channel as location.
