Well, HTC is confident enough on Vive to sell part of its phone business to Google instead of selling the VR part. That should be enough of a proof. But of course, HTC isn't Facebook and they need to make money from it.
Also, the Vive is still the best VR solution (helmet, controllers and tracking system) out there.
We'll see just how long they hold onto the VR dept and pushing more with it.
Yes, Vive is the better headset in terms of performance and tracking, but it's no good if the company drops it within a few more years.