Great rant... except that the window to be a world class athlete is not mid 20s to late 30s. Thats what too many people on here argue.
Go ahead and look up the fastest 5k and 10k times ever run. The average age of the PR for a top 5k runner is 21 years old and many of these runners were in there prime at 18-20 years old.
Kenenisa Bekele (ETH) Age 21 12:37.35
Haile Gebrselassie (ETH) Age 25 12:39.36
Daniel Komen (KEN) Age 21 12:39.74
Eliud Kipchoge (KEN) Age 19 12:46.53
Dejen Gebremeskel (ETH) Age 22 12:46.81
Sileshi Sihine (ETH) Age 21 12:47.04
Hagos Gebriwhet (ETH) Age 18 12:47.53
Isaiah Koech (KEN) Age 18 12:48.64
Isaac Songok (KEN) Age 22 12:48.66
Yenew Alamirew (ETH) Age 22 12:48.77
Stephen Cherono (KEN) Age 20 12:48.81
Thomas Longosiwa (KEN) Age 20 12:49.04
Average Age 20.75 years old