The webstack is still a mess.
And most of what people actually want in a day still comes from proprietary applications. Sure there are open-source equivalents to things like Office - but who actually uses stuff like Open Office and Google Docs other than their parent company and tech enthusiasts?
And is Google or Facebook or Twitter (or let's face it Mac OSX or all of Android or all of Chrome) open-source? Nope. Didn't think so.