OK, so let's do the math. There's about 25k high schools in the USA. Let's suppose they all have a track team, and let's assume that they all have 5 team members who can break 04:30 for 1600m. Sure, at some schools that's too few, but at others it is too many.

That gives us 125k high schoolers in the USA who can break 04:30 for 1600m. There are about 18M high school students. So of just the high school population alone, about 0.7% of them can do this.

Assuming there are the 4x as many adults that can do this as there are high school students, that gives us slightly less than 0.2% of the total US population capable of this.

I rest my case.