Why didn’t Google make a fast move and buy OculusVR?

From Google’s perspective, it seems like a big mistake letting Zuckerberg and Facebook get to Oculus first and buy them. Google, who have recently been making a big effort to market themselves as a very futuristic company, seem to have missed out on a big chance at consolidating their power over an extremely important area of future technology.
I would consider virtual reality to be one of the upcoming revolutionary disruptive technologies, that will change the world forever in ways we cant yet imagine. In a few decades VR will be considered so impact full that it will be recognized as the television of the 21st century.
Right now, OculusVR seems to be emerging as the leader in consumer VR, and it is clear that Zuckerberg considers it the next big computing platform after mobile. How Facebook plans to use Oculus in their grand design is still somewhat mysterious, but ideas are floating around that Facebook plans to build a billion-user online virtual world through virtual reality.
Google had a lot to gain from buying the leader in VR:
The CTO, John Carmack is widely considered one of the best graphics programmers in the world and an incredibly smart engineer.
Google doesn’t have the world’s number one social network it can use to leverage a user base (like Facebook), but that shouldn’t really matter; it has Youtube, which itself is vastly popular, Youtube is already hosting 3D video viewable through the Rift.
It could have extended this by having a "Steam"-like App store for all kinds of VR content, a sort of meeting ground between the vastly popular Google Play Store and Youtube.
On the other side of this fork, Android has a huge and enthusiastic user base, and Carmack with Oculus is already working on a standalone Rift powered by Android.
If Google ever had ambitions to get into the gaming space (which it is already doing with the Android Play Store), leveraging the new frontier of VR through Oculus and Android would be a match made in heaven. It just makes sense.
Google were very serious about acquiring Whatsapp and they lost it to Facebook, now Facebook has the leader in a key technology for the future. Google recently seems to have a had a heavy focus on investigating new futuristic technologies, such as driverless cars, but has a particular interest in wearable technology (such as Glass and Android Wear). It may seem therefore that the futuristic ambitions of Oculus would fit perfectly into the ambitious "Moonshot" innovation culture of Google.
A $2 billion commitment would have been nothing for Google, especially to acquire the technology leader in an emerging new platform. 
I wonder why they didn’t move sooner?