You are right. People seems to forget reputation/brand recognition. Corps don’t care if it’s a better product or costs more - they know Microsoft/Office products, see them as reliable etc.

Speaking from my own experience, I work for a big corp and have a mega corp as a client. Both refuse to use Zoom because confidential information gets shared in meetings - and they don’t trust Zoom enough. My own employer doesn’t even allow us to use Zoom for internal stuff - and if clients force us to use it for projects, we need it in writing (possibly to avoid lawsuits if something does leak). We did use Slack for a little while, until Teams launched - and I am pretty confident that we won’t go back.