But presumably they originally chose 26 because that was how long the route round the parts of london they wanted to route it round were originally, and then it has stuck and is the yardstick for any marathon wherever.
Yeah, and then the Greeks* stole the idea ...
Back to riding 100s:
You're right, I do suffer lack of motivation to ride 100s now. But there's a subtlety to this:
by riding them and getting validated you're boosting the organiser's figures on AUKweb, so there is (kind of) some point!
So ....
If something like RRTY** was on the line, I'd choose the 200. But generally I'd ride out to the nice 100 Calendar event, mainly for the company etc.
(**for others, substitute seasonal points target, AAA points, an SR etc ... etc ... !)
(*Spartans? Oh who cares ... )