You can easily run client-side only web apps. It's not Google's fault that developers would rather serve up code from their server.

Check out this editor: http://www.mrdoob.com/projects/htmleditor/ https://github.com/mrdoob/htmleditor

Runs entirely client-side, you can download the files, open in a browser, and voilà, full functionality.

Apps like this are the promise of the web, of OSes like Firefox OS and Chrome OS. It's only developer imposed limitations that are to blame, much like online-only DRM in native apps...