I cannot imagine that Facebook will be able to compete with whatever Apple has planned in the AR space. Every platform advantage that made the Apple Watch incredibly difficult to compete with will be so much more important with AR.

This is particularly evident when considering Apple's lead in silicon, which will allow Apple's AR products to be lighter, faster and longer lasting than their competitors. Apple's vertical integration means that there should be more AR "apps" and better software integration than any of their competitors. Apple's pro-privacy push means that consumers will be far more willing to strap Apple branded AR glasses to their face all day.

Facebook might be able to out-compete Apple in VR (silicon performance and efficiency is not as critical for VR), however VR likely will not have the same mainstream appeal that AR will have.