In our org, at least, it's also the latest example of MSFT winning partly by being everpresent and partly by stumbles from competitors.
We are 100% work from home -- the company has no offices anywhere. Consequently, we do a lot of online meetings, with an emphasis on screensharing. (I don't think we've ever turned on cameras.) Our standard for a LONG time was GoToMeeting, because while it was more expensive, it WORKED every time, including and especially when we used it with customers.
But GTM got sloppy, and Teams was suddenly everywhere, and then GTM messed up their easy Outlook integration, and all of a sudden we were using Teams.
That said, the current state isn't that much better; they do have an app store at the moment, but all the alternatives are still there as well. Developer tools you install via nuget or chocolatey or whatever, games via Steam, Epic, or each individual developer's launcher, loads of stuff you just get via a download off a website, etc.
I loathe using that app.
And it's been like that at at least 3 or 4 companies I've worked at so it's not just this specific organisation.