As of today, we have no path to supporting Vive without integrating Steam/SteamVR/OpenVR. This is exactly the way Valve wants it. [...]
We really did make an honest, good-faith effort to natively support Vive at the same level of quality we support the Rift, with access to all of our platform features and content. It could be that we would have chosen not to pull the trigger and go ahead with it in the end, but we never got far enough to have a choice - Valve made that impossible for obvious reasons. Valve gains nothing by letting Oculus support natively without SteamVR. They know we have a better SDK, they know we are going to have a broader / better content lineup, they know all the things I talked about above. As long as Valve stays stuck to their platform, they win. The real twist in the current situation is that as of now, they get to have the ideal business decision AND the ideal PR! We take all the hits, we play punching bag, and they reap the benefit. [...]
Valve gains a lot by effectively locking Vive users to SteamVR and their ecosystem. The current situation is basically the only reason they can get devs to target OpenVR/SteamVR and by extension, Steam: If the Oculus SDK supported Vive (or alternatively, if Vive did not exist), no developer would bother using SteamVR. Why would they?