I like the way Bob Katz says it,
"What's the rush in mixing in surround if you haven't mastered good ol fashion stereo?"
surround is great when it works, but the likelyhood that it happens often is rare. Plus, if you really look into how the best surround mixes are done, you'd be surprised to find out that it becomes sort of a glorified stereo.
For example, I was reading an article on the guys who did up one of the Coldplay live DVDs in surround. He basically mixed all the elements of the band on the L,C,R channels (in the typical fashion), then leaving the surround channels for ambient stuff like crowd sounds and reverbs.
So the end result is a lifelike experience, but not that it can't be done close enough in stereo.