UFC had a chance to do exactly this by signing Quinton Rampage Jackson. I thought he would fit the UFC perfectly because of his personality and fighting style. Of course he also beat Chuck in Pride so that would have setup a big rematch between those two. Also Chuck is 37 so it would have been smart to have another big star in the wings to take his place when he begins to decline. So when they didn't sign him, I was hugely dissappointed. A 205lb division with Chuck, Tito, and Rampage would have been awesome.
IMO it looks like UFC at the moment doesn't feel like they need to sign any more big names and thus pay big money in order to succeed. It's like a basketball team where you have a few highly paid superstars and the rest are average, maybe UFC feels they have enough superstars now?
I think that's a mistake as you grow the sport by putting superstar fighters out there. For example more people watched golf because of Tiger Woods.
Maybe when they feel a little more desperate will they shell out the money for another big fighter.