So as you say, most were already using something non-Zoom, that's the up-thread point - where did Zoom come from.
Also I doubt Teams was a minor player, in usage maybe but not availability - it has a free tier I think but otherwise comes with O365, which is obviously not minor. Having it doesn't mean you use Teams, but it does mean that it ought to be an obvious choice if you suddenly, newly, have a need for a product like that, as so many companies did.
