To your first question I think we need to consider how important Private Messaging is to any social network. And I think this article/post did a great job explaining it:
https://steemit.com/partiko/@stellabelle/5-reasons-private-messaging-is-critical-to-any-social-network-including-steem-67mjijij

Right now as you mentioned crypto is not "user friendly", which means there isn't much a single coin can do to attract the "masses". It will all depend on the biggest coins until we reach a level where new projects can have a significant impact.

What I mean by that is, we need to promote crypto first, and only then we will be able to market dApps and all those good projects.