The author makes the leap from "data is live-synced between multiple running applications" to "applications that can run on multiple devices simultaneously" erroneously (or, to make a different point). They're quite distinct technologies that are not mutually dependent on eachother. In fact, this tech could be applied to web applications to also interoperate.

Web applications are run-anywhere, but are not live-synced. Google Docs are, but not web applications as a whole.