I think you're understating the strength of weak connections. If I have even one friend who's not on Whatsapp that I want to stay in touch with then I'm going t

I think you're understating the strength of weak connections. If I have even one friend who's not on Whatsapp that I want to stay in touch with then I'm going to download another app. If there's a group chat with this person then everyone in that group is downloading a second app. And then second degree and third degree connections get affected too. Getting out of the EU would be a massive blow to any established social media company that depends on network effects. It doesn't matter as much for smaller companies that are still growing (eg. early Facebook still managed to grow by only offering services to college students).