OK, so after a deluge of responses, I think we're finally getting somewhere with this. Thanks to the guy who offered a clear data point. Others were just way off the discussion thread, having not read through the entire thing.
Here are some cited reasons for racing which, though I may not agree with or find personally applicable, do have some legitimacy:
1- It's a social event. The atmosphere..the friendly rivalries...the race within a race...the vibes...the energy
2- It sets a good example for the kids
3- It provides a break from the rigors of running day in and day out
4- I can set age PR's
But the rest is bullshit. It ain't about competing, winning, running a lifetime PR, getting better over time,
bc that's not possible anymore given the initial conditions