I disagree with the authors premise that there can only be 2-3 behemoths. Has he not been paying attention to how kids use mobile apps these days?  No one is locked in to a single ecosystem like they used to be.<p>People use gchat, Facebook, Instagram, snapchat, whatsapp, and iMessage simultaneously, for distinct purposes. And all of their friends do too.<p>As long as the app present value, kids these days have no problems switching back and forth between apps, meaning they can get hundreds of millions or billions of users too.