Really, from 2008-2012, it's mostly been a one-man toy project. It's only since mid-2012 or so that we've had many different people working on it.

Until early 2014, I along with my team at Red Hat were busy building RHEL7. RHEL7 development has slowed down now, and full-time Wayland development has started.

The thing is, Wayland is a simplified display server that basically pushes all the hard problems onto others. So for instance there's no rendering code (that's handled via existing projects like Mesa and Cairo), no graphics driver abstraction layer (new graphics drivers are expected to fork Wayland), no seperation between window manager and display server (fork Wayland to change anything!), the input implementation is largely copied from X, network transparency and remoting are Some Else's Problem and require co-operation from app developers...