What I'm saying is that for the majority of people, even those who are considered "fit", don't default to aerobic system of energy when doing endurance sports because they don't have a solid enough base. They think because they're going for a 30 minute run it _must_ be aerobic, but if tested, they'd find it wasn't.

To know if this is true or not would require testing and numbers and defining what's considered "fit", rather than commenting on HN. That said, I truly have relatively high confidence in that the active population these days very much relies on the glycolytic energy system rather than oxidative, anaerobic rather than aerobic.