Engines never want to fianchetto?

I use the SOS 5.1 Engine with Arena, and I've noticed that the engine will nearly always consider fianchettoing a bishop to be an inferior move, even in positions where it is strongly the main line (King's Indian attack, Sicilian dragon, etc.). Can anyone explain why this is the case?

Also, do the top engines like Houdini and Rybka have this same aversion to fianchettoed bishops? If so, why?

My guess is fianchetto offers a long term advantage and the engine doesn't factor those in.Computers don't think positionally, so they just look for the best tactic.

I never paid much attention to this, but aren't fianchettos normally done while in the opening book? So it would be more of an opening book design issue, right?

I just remembered that Hiarcs does have a hypermodern setting, although I've never tried it.