The OP disagrees.

• First, note the number of responses to this thread and the length of many of the responses.
• I think most of us record our average speed if we keep a log if we keep a log. And I think most those with no log probably note the average speed after a ride.
• Also, I am pretty sure that the majority of riders in this forum (50+) and overall in Bike Forums strive to improve their riding. Many resort to even changing their diet.
• In this particular forum, I personally address age-related issues. I am 68. I cannot keep pace with most younger riders (I've done a lot of group rides) but I can with a group that rides on Wednesday morning - almost everyone is older. But I, and a lot of others, would like to quantify that difference.
• Yes, I agree that Ironman athletes are different than most of us. Note that my final chart uses 20 mph as the "standard" as the starting point for comparison, not Ironman or TDF average speed.
• I wanted to know who my 14 to 16 mph compared to other riders.

Ironman athletes are not the same as most of us. They are quite spectacular. I did not compare them to "us" - I just used their data to measure the relative strength between different age groups. There is a problem doing that, because the drop-off in performance for super-athletes is undoubtedly less than it is for "regular people." I might be proven wrong, but I expect that "their" results are not very different than "us." -

We may not be super athletes (mostly), but we are athletes (mostly), and I think our rate of performance drop is closer to Ironman contestants than it is to sedentary people.