Earlier quoted context omitted.
I've never used Telegram, but I suspect the Teams integration with SharePoint/Office365 and the (terrible) way Teams tries to be cake icing and floor wax by integrating file store, wiki, document library, telephone, whiteboard, plugin app ecosystem and webhook scripting environment with Windows ACLs makes it more complex than an independent chat/call/video call program?
Perhaps a bit? But as others wrote, they have 50 people. How many does Microsoft have (and of course, Google, Facebook are also bad at it)
Don't get me wrong, I loathe Teams and its laggish bullshit nature as much as the rest of the pitchfork wielding people in this thread, it's just that it's not apples-to-apples comparison with a pure chat/call client and the headcount needed to develop it because of how much extra junk is hiding in Teams.