Understood, but remember that the mass market doesn't care about open standards. They care about a tool that works for them. Open Office isn't used much by the mass market, but Google Apps is. The more someone uses the service, the greater the probability that someone will come around and standardize the protocol. But, I agree it may take a while.
Right. I'm not talking about the public caring about open standards though, what I mean is anyone at all can run an email server, and they all interoperate, so everyone's email talks to everyone else's. The public doesn't know how that happens, but the utility of email between everyone in the world is much greater because of that. No one wonders if anyone's email can talk to each other.
Email, obviously, is one pro example of what I'm talking about. A con example is your Docs example, you only get that on Google (and maybe MS is in early days, I don't pay too much attention to them), and yet it is counted in the "success" column, I think.
If G+ is replaced by something as open as email, implementable by anyone, then yeah, maybe. But not until.