Designers and developers are essentially doing the same thing...
...they're solving business problems.
In their latest Channel 9 video [1], Kevin Moore and Robert Ingebretsen talk about how Windows Presentation Foundation (WPF) affords the beauty and visual flexibility of the Web but with the richness of the Windows platform rolled in. They also talk about designer-developer workflow. Robert makes the point expressed in this post's title and goes on to say that WPF lets designers and developers "work in the same space," yet solve problems in the way each is used to.