Lobbyists at the EU have gutted the definition of "open" (part of a proposal to require more open standards and open source tools in European government) to mean "the willingness of persons, organisations or other members of a community of interest to share knowledge." This meaningless drivel replaces a more robust definition that included, "The standard is adopted and will be maintained by a not-for-profit organisation, and its ongoing development occurs on the basis of an open decision-making procedure available to all interested parties (consensus or majority decision etc.)."
According to this line of thinking, if everyone were forced to use Microsoft Word for document interchange, then that would provide interoperability. Except that it wouldn't, because interoperability implies at least two *different* things are are operating together: self-interoperability is trivial. Version 2's "homogeneity" is better described as a monopoly and a monoculture - and the last two decades have taught just how dangerous those are.