But then would you still be able to say “most” are below average of the distribution is normal?

If we assume intelligence is a normal distribution, then we can say half of the population is below average. I think it's fair to categorize half as most.

“Half = most” is… innovative. I like to think of it as “half = so many that you’ll run into a lot of them.”

By "most" definitions, "most" means more than half. So we're literally arguing over a single person.