Sure, totally agree that it'd be great if this was a low level feature of the OS that seamlessly integrated with any possible GUI for authentication from readline and up. But we could sit here all day and enumerate ways in which open source operating systems and desktop environments are less integrated than others.

All I was saying originally was that KDE was the first Linux environment I used which came close to the level of broad support and integration you get from something like Windows, and in some cases it went beyond.