FWIW, this kind of comparison can become even more discouraging as you age. At 58, I'm pretty sure most of my PRs are behind me. The amount of training I'd have to do to get back down to my peak numbers is way more than I'm actually willing to do, and there's a high likelihood that such a high work rate would end in injury instead of success. Instead, I track how each run stacks up against others within some time period - a year, two years, five. A "two-year PR" feels pretty good. A "five-year PR" would be awesome, even if it's short of my all-time PR. I wish Garmin or Strava or whatever would support this kind of thing better.