That ignores the fact that those apps may have done even better had they invested in native alternatives. I don't think it's a stretch to assume that there's s

That ignores the fact that those apps may have done even better had they invested in native alternatives. I don't think it's a stretch to assume that there's some non-zero set of folks out there that tried to switch from Exchange/Outlook to Slack at scale and said "this doesn't really meet our needs". Some of that is UX, sure, but that UX was also driven by the limitations of performance. How big is that non-zero set? Who's to say, business is hard and full of imperfect assumptions. But I can tell you as a user of most of these apps, having them not do what I tell them to do because of laggy UIs is infuriating. (E.g. I constantly make the mistake of "reacting" to someone else's message in Teams while I'm trying to find a permalink or edit my own message. Then they get a push notification, I erase the reaction, and I hope they assume it was a mistake. Happens every couple days.)