I'm 66 and I set the bar about 1 or 2 inches below the saddle as opposed to 4 inches 30 years ago. I also use shallow drop bars on my main road bike.
Stretching may be beneficial in some ways but some of us are just less flexible as we get older. Some of this is skeletal, as others have said. Old injuries, arthritis, joint pain, etc. I'm still riding a very stiff frame and do have aches and pains after several hours on the road. A lot of the roads around here are in bad shape.