But I've found that the vast majority of regular old users invest an incredible amount of themselves into learning an interface. I know people who still use WordPerfect for DOS because they couldn't move beyond their investment in the interface and moving to not just MS-Word, but WordPerfect for windows was too much of a jump.
Outside of the tech-sphere, users don't click buttons or dig through menus to figure out what they do or where things are, they might mouseover for a tooltip if your lucky. But most users don't explore. They learn and regurgitate procedures. Do this to make something bold, do this to indent a line, do this to insert a picture, etc.
There's no reason for MS-Office classes, yet they abound everywhere because non-tech users simply don't do these kinds of things. Putting as much up front as possible, with labels on as much as possible is about the only way you can get users to see that, yes, this software can do something.
It's mind-numbing and frustrating as an interface designer to spend hours thinking of optimal workflows, and minimal menu depth and all that, only to have users simply not use those things because it doesn't follow a procedure they happened to have learned a decade prior.
What is interesting is that the Ribbon is an improvement, but only for novice to average users. In various surveys and studies the only segment of the population that seems to have a problem with it are relatively advanced or technical users. High-end users report a loss of productivity. But increasing the capabilities of novice and average users was the goal of the interface and thus it has succeeded.