That's true, but on the other hand, there are many apps that are pleasure to use where a web site is a pain in the ass. The android gmail app comes to mind.
I think that people are more likely to pay for an app then for a website.. maybe that is why, Apple, Google & Microsoft are pushing apps instead of pushing the web..
This is a good point, and touches on what calebbrown said above, that apps are concrete, which makes it easier to pay for (psychologically). Perhaps the powers that be recognize this, or perhaps it's just a matter of the biz end of then interent starting to trend towards paid material. Money drives motivation here. This scares me a little, because it tells me we really are going to move into a world of apps....