But your friend groups would probably be able to migrate to Signal/Discord/Hangouts/etc quite quickly if WhatsApp were to disappear, no? WhatsApp has the network effect on its side by way of existing, but that could change quickly if given a push.
Sure. But you might not get everyone back - you'd have to have an alternate method of talking to the folks to get them to switch and meet up in the same place. You'd have this if the service just slowly died (like landlines), but not if something breaks instantly - forever. I'm guessing we've all had this when games died (especially old text-based MMORPG's, for example. So many people gone).
