Can web apps replace the traditional desktop office suite?

A few weeks ago I saw an article about the Office Web Apps adding header and footer support in their Word Web App, as well as many other features in the other web apps in an update that is set to arrive in the coming months (not sure how long it's going to be though.

Over the past 3 weeks that article has gotten me thinking about the potential for web office suites like Google Docs and the Office Web Apps to eventually overtake traditional desktop office suites like Microsoft Office and LibreOffice.