Yes like I mentioned in other reply, you can move regions and carry your wait list time. But many people are tied by job and family. Also insurance plans sometimes have preferred hospitals.
As for why I haven't tried a shorter wait region, I consider transplant as not a cure. It will eventually fail. And there are other things in progress like the UCSF artifical kidney, gene therapy research, better anti-rejection drugs. My hope is when my transplant does fail, one of these alternatives are further along. So I look at each of these things as stepping stones to extend my life.