Sega is plenty smart when it comes to software (i.e., games). When it comes to hardware, they haven't done anything smart since the Genesis. That being said, what makes Sega REALLY smart is dropping out of the console market to concentrate on their strength, games.
The install base just isn't there for a mature game like GTA. I seriously doubt Nintendo will ever allow the level of sex, drugs, violence that is included in GTA games to appear on their kid-friendly systems.