Like Facebook and other networks, the fundamental problem is that you need “everyone” you interact with to move to the new thing at the same time, otherwise the new thing is basically useless.

At this point in time, I feel like the solution is more likely to be based in laws (e.g. “seamless export/migration must be supported”), and not in technology. That way, at least you remove the friction of having to recreate an entire profile, etc. on a new platform, and you “only” have to convince all your friends/colleagues to try migrating to the new thing (automatically).