I'm kind of curious as to why you think that Valve will be firing most of their VR team. Do you think that they have fully proven that VR is possible and done what they can without going in to production?
If I'm not mistake I believe that a handful of the VR people are also working on the steambox and controller which still has a ways to go.
Last year Valve did "mass" (relative to the size of the company and divisions) firings [0] after Jeri Ellsworth was fired. Right now it's just speculation, but I doubt Valve has either the time, money or motivation to compete against two giants, Facebook and Sony, and against the other new competitors that are starting to appear [1][2][3].
Valve's hands are already full with the SteamBox, the controller, Steam itself and however many games they have in development. But yes, you're right - some of the VR developers might simply be relocated to other projects within Valve. Who knows.
You say it's "very likely" that Valve will fire certain people, but when pressed your reasoning is that they fired some other people in the past and are involved in a number of projects.
But the AR guys' project was seen as a failure, or at least as a poor fit with Valve, they apparently weren't very interested in working on Valve's other projects, and there had been antagonism between them and the rest of Valve. I don't think there are similar problems in this case.
If I'm not mistake I believe that a handful of the VR people are also working on the steambox and controller which still has a ways to go.