My bet is on Valve being the dark horse in this race. Gabe already has expressed interest, they're assisting development on Garry's Mod 2 (s&box), and they have the highest quality VR hardware. They also have consumer trust, everyone with VR has a steam account, they have a method of sharing user-generated content (and making money off of it!) with the workshop. If they can coordinate, they can take off in this area