its too expensive.. [its not wide and close enough focal length].
As far as I see it, the 24-70ii is designed as an event and wedding lens to work in combination with Canon's other standard for these occasions: the 70-200ii. I guess Canon figured that when shooting people, you don't really need IS for this zoom range because of the min. shutter speed for moving objects, and that for professionals it's in the exact 70-200ii price range they're used to get for their work.
very good point!