Not so fast with the happiness! You lost 1" in 3 years. I calculate that in ten years as you hit 73 years young, you will be about 5' 6.7" or so. In addition, if every 3 years you need to reduce your stem by 10mm, in ten years you'll need about a 66mm stem.
On the other hand, I tell me wife if you ever can't find me, look in my shoes. I may have shrunk out of sight.