Half Life VR is honestly exactly the thing I've been wishing for - both for the industry and for the series. In fact, I posted that in the thread a very long time ago.

They couldn't have delivered with a "normal" Half Life 3. The expectations are unreachably high, but with VR (and it being a prequel) you are both lowering expectations because the broad audience still thinks that VR is a "gimmick and a fad that will fade away" while at the same time setting up an extremely pleasant surprise for people who hadn't tried VR before but will experience it's marvels for the first time in this Half Life title. 
It would blow them away. The game itself doesn't even have to be great, it simply being VR and some physics shenanigans will be revolutionary enough.

I hope it will also give the industry a significant boost in users or at least attention, though I am not expecting a drastic paradigm shift.