I think more specifically, and not disagree, it's more those categories of (development) tools require a network connection to begin interfacing with them. With that said, if all that is required is a network connection then the browser would seem certainly the best platform. It is the most prolific means of interfacing with them (network connections).

Now that web apps are "grown up," and properly competing, we're seeing where they're better than desktop and also insufficient. I think it's safe to say, when the only requirement is a network connection, then the browser is the obvious choice! :)

... well I guess an argument could be made the telephone is a more available network connection-- but I don't want to dial in my database commands ;-)