I think Lee and Dunn are similar, but 2006 was the year that Lee signed his big contract and he was older than Dunn, just as bad on defense as Dunn, and his offensive production at that point in his career wasn't where it is today.
We can argue all day if Lee is "much better" than Dunn TODAY (even though he isn't), but the point is where Lee was after 2006 (before he signed the longterm deal with Houston).