There is nothing stopping other stores from selling games for the HTC Vive.
As for OpenVR (or SteamVR, Valve's implementation of it), I'm not sure it makes sense to ask whether the Vive is tied to it. Is your graphics card "tied" to your graphics driver or its OpenGL implementation?
The current situation, as MrRadar said, is that games can support OpenVR and headsets can adopt OpenVR without seeking anyone's permission. Compare that to the situation with the other leading VR headset and make of it what you will.
Currently Steam is the only game store that supports the HTC Vive, but as Valve co-founder Gabe Newell has said: https://reddit.com/491hu4
And the leaked HTC Viveport demonstrates: https://www.vrfocus.com/2016/01/htc-viveport-store-is-option...
There is nothing stopping other stores from selling games for the HTC Vive.
As for OpenVR (or SteamVR, Valve's implementation of it), I'm not sure it makes sense to ask whether the Vive is tied to it. Is your graphics card "tied" to your graphics driver or its OpenGL implementation?
The current situation, as MrRadar said, is that games can support OpenVR and headsets can adopt OpenVR without seeking anyone's permission. Compare that to the situation with the other leading VR headset and make of it what you will.