Of course I can, particularly if they are best-in-class in a class that is not relevant to me. I'm not going to use web apps for email or for office documents, except for edge cases. And that is the case for most people in the world, web apps are a nicety, but not the primary use case.

Maps, as I said, are different.

I think you're extrapolating your opinion to "most" people. Gmail is extremely popular, and while Docs is no Gmail, it has no serious competition for cloud-based editing.

Even if you're not using Gmail's webapp, it's an entire email infrastructure serving as the backend for Mail.app or Mailbox or whatever you use. At this point, if someone doesn't have their own mail server, they're probably using Gmail.