Plasma Mobile has the right idea. Build the platform, let communities form around the layers above it (and below it) and just try to get people working together on one goal (especially since all these mobile OS projects are all using Qt, all using Wayland, all using Linux). Lets just hope the KDE guys don't vaporware this one like Plasma Active, it sure would be lovely if Unity 8 got rebased on top of it, and used xdg-app like the community is pushing towards. Firefox could even get in on it as the default browser with great integrated webapp support.