Because most team don't data mine. (Note that Houston--who does data mine--came the closest last year, but decided understandably on Yao Ming, Chuck Hayes, Brad Miller, and (briefly) Hasheem Thabeet.)
And because while big men who can defend (or disrupt) are in short supply, too many teams want offense--or want a player who has the potential to consistently play both. Even Utah might possibly have multiple 4/5s who produce on both ends of the court--if Big Al can learn to help, if Favors can learn to post, and if Kanter builds on his Euroleague experience.
I actually like posts that have been "edited" as it shows that the writer is thinking things through...