It most certainly happens. I have had 6.5yo bucks that couldn't break 100" if they wanted to...that's the thing about genetics is they are completely unique [emoji3]
You just never know. I killed a buck 2 years ago believed to be 6.5 and I had pictures of him for 3 years. He never put on a good set of antlers until 6.5 yo. He was not impressive at all at 4.5