I'm not sure this is entirely fair, given the blog post clearly tries to mention the other folks who are working in this space. Specifically for the "missing communications/data layer" for VR, the only other options I personally know of are High Fidelity (decentralised, but not yet trying for an open standard or to use the open web), OpenCroquet/Cobalt (seems fairly dead since 2010), OpenSimulator (not decentralised, afaik), and there have been some talk of JanusVR + IPFS hybrids.
Empirically, there certainly is a missing layer here, and it doesn't seem unreasonable to propose Matrix as a possible solution :)
In terms of "this will happen organically, rather than as a whole new virtual universe appearing out of nowhere"... we see AR and VR as entirely the same problem from a comms/data interoperability perspective. Both of them need somewhere to store the data. The choice is simply whether you store it in a decentralised DB like Matrix, IPFS, a blockchain(!) or whatever... or if you store it in a silo like a typical VRML or WebVR app, or something like Google/Facebook.
I don't blame everyone for being cynical though - this is the holy grail after all :D
