Big bucks are definitely wily, elusive animals. I think the rest of the state just has more deer, so chances are higher of seeing them. Granted, avg antler size will be larger in Middle and West TN, but a big buck is still going to look like a big buck.
A buddy of mine saw a 130ish deer in August near my parents house. Hasn't been seen since. I know there are some good ones staying in the area, cause the neighbor has killed 2 over the past 4yrs in the 130-140 range. Both killed during the rut, right at dark. I have yet to see one that size in E TN, except in Cades Cove.
When I visit my in-laws in Murfreesboro, I sometimes see big deer along the way, but I also see many more deer than I do here at home. I really think its a population thing.