The only problem I have seen with web applications is that everyone wants EVERYTHING on the web.
Unlike the rest of the world I take the position that even though the web is great, there are some applications that do not ever need to be "on the web."
This is vague, but there are LOTS of applications that have high UI requirements that will never be successful on the web.
Most web applications are consistent because of lack of controls to choose from. If you want to run everywhere you are limited to the most basic controls and as you said no menus. Lack of choice in this case is a good thing.
If you ignore flash as a web development platform there really are no choices. There are choice in the plumbing... how you get the textbox to the browser but in the end it is at best still a textbox.
My point is that in the end, you really still have a textbox. And for the most part a textbox that you cannot really do anything with, other than read values once a submit button is pressed.
Are web apps really just an alternate reality where we are all working in a really bad version of VB?