Eh, you are comparing two completely different things. Steam machines did fine, and they are not the ones taking the hit anyways. The Steam Controller is awesome and keeps getting better and better. VR is something much bigger than Steam Music and they are already developing what will be the main VR Api, and that is all that mather. They don't need killer app at all, they don't need to HL3 VR at all. All they have to do is keeping improving their Api and headsets, and the games will come, both from AAA and indie devs. There doesn't need to be a super huge mega ultra AAA game for VR, only a steady offering of high quality software. This is what they said, and they're right.
And who will provide that HQ software? Oculus at least financially supports projects so devs are going to them because it is safer to get some/all money in advance. Launching software on new platform is extremely risky and that is why you don't see big publishers doing VR (Except Sony but even they are doing smaller projects). Valve with one game could sell significant numbers of Vives that would then give more reason to other devs to go and do games/apps for VR.