But there’s also an alternative theory about the deal: Oculus, which was a clear first-mover and leader in its category, may have been motivated to sell by something other than Zuckerberg’s grand vision. It was facing competition from fast-moving, well-funded competitors entrenched in the industry. Namely, Sony (SNE) and Microsoft (MSFT).

Oculus’ virtual reality platform has generated a gleeful excitement in the gaming community. The company started out with a crowdfunding campaign, raising $2.4 million on Kickstarter. It went on to pre-sell 70,000 developer kits to game makers building virtual reality games for the headsets. (At $300 and $350, that’s around $22 million in revenue.) Eventually, Oculus raised $93.4 million in venture funding.

But just this month, Sony revealed “Project Morpheus,” its own virtual reality competitor. And Microsoft is rumored to be working on its version to work with XBox.

Given how Sony has essentially matched Oculus Rift so quickly, sale to Facebook makes sense. They’ll need lots of $ to compete.

— NathanOlivarez-Giles (@nateog) March 25, 2014

On a conference call, Zuckerberg dismissed this notion. Oculus is far ahead of each competitor in terms of product and its stable of talent, he said. Beyond that, Zuckerberg noted that whoever wins in this category will need to fuse social media with virtual reality.

About 40% of time spent on Facebook overall is spent with gaming, and about 40% is spent in social communication, Zuckerberg said. Sony and Microsoft don’t have social media chops, he said. But Oculus and Facebook do. “In order to build a really big computing platform … you need to fuse both of those things together,” he said. “Either of these two companies are the only ones that are set up for that to happen.”