Earlier quoted context omitted.
Of all the big tech companies Facebook is the only one where it can completely disappear overnight and my life would be completely unaffected (or possibly improved by not having to explain to people I don't use facebook, please email or text me your invitations rather than use messenger). If Google, Amazon, Netflix, Apple disappeared the story would be completely different.
Maybe Google, because of the search engine. Android: somebody will fill the void. Messaging: people have been switching on hordes to every new free messaging system in the 90s and early 2000s, we will adapt to something else. Netflix and video in general: same thing without the 90s/early 2000s. Amazon: very convenient store, we'll spend a little less and somebody will fill the void. Apple: can't say, never bought any…
Back then the IM population was a lot smaller. Also with "Free Basics" and other things in some regions of the world Facebook plays a game which makes it impossible to switch. (Using Whatsapp is free, for others one ahs to buy mobile data credits)