I observe that people "expect more functionality" from a desktop app, than a web app. Why?...because the desktop offers more tools for the developer to use. Web apps are severely limited by the web-browser interface, cgi restristions, etc. Whereas the desktop app has the option of which GUI interface to use, more access to the filesystem, etc. So, with more functionality there should be a "higher learning curve" for the user. I think we've all experienced the dissapointment of starting up a desktop GUI app, and finding it is no more than frontend for running a commandline program, without all the options available on the commandline. So you have to put all those options in a menu, which requires the end-user to know what they mean.
I suppose you could design web apps to do this, but I guess the old adage "write for your audience" applies. It does seem that the general consensus is that the average web user is not as competant as the average desktop user.
I'm not really a human, but I play one on earth.