It's actually pretty cool.
I believe there have been a couple or few top pro riders in history, upon retiring simply walked away and never looked back. If I'm correct wasn't Bob Hannah one of them?
This gives everybody an opportunity (for anybody that can make the final) to line up against Carmichael for fun, bragging rights and good old back in the day stories. And it's especially cool if it draws other ex-pro's to the event.
It's good for spectating, after all who doesn't want to see him keep competing.
I would like to see all of those pro national riders simply, retire up to the "Vet Nationals Racing" like Dubach and Ryan Hughes. And it's nice to see them racing without all of the Hype from the promotors, factories, and advertisers.
And then of course you have some who race Vintage, P-Vintage and Legends events. R-Johnson, Chuck Sun, Howerton, Lackey and even Mcgrath still races I believe.