Which means we should be practicing reinforcement of those "outer limit" skills until responses are second nature and to me that means "track day".
We're never going to get that by only riding on the street unless there's Something Horrible getting ready to happen, are we? How often during regular riding do we practice threshold braking or rapid changes in direction?
People not getting trained and then not keeping those skills current gets people killed, IMHO, so I'm a big fan of ongoing training. I used to run into people back in New England who skied and rode bikes. They'd take ski lessons every first day of skiing, but not for motorcycles, so I'd ask them why not? Which activity do you do more often and does it have the potential get you killed?
I don't think people ever actually thought about it once they'd passed their license test.