Of the great many runners I ran with as a kid, and was aware of from schools in our large league, then also from my kids' teams and their leagues, here is what I have seen.
I know of about 50 or 60 kids from both eras who were 4:40 or faster freshmen, covering about 15 years in more than one state. Three were eventually sub four minute milers during their careers. By age 16, all three were huge stars in high school, in part because, by some very long odds, one of them was the #1 miler in the country and became the U.S. record holder. Another was super young and became a 16 year old senior who was sub 4:15, then went sub 4 around age 20 in college. The third was more steady, but still was sub 4:10 in high school as an 18 year old.
Most of the sub 4:40 frosh I know of did not run collegiately. I would say about half never broke 4:30, with some focusing on shorter distances, some with injuries, taking up of other sports, drug use, lack of interest in running, etc. I know of about ten who became sub 4:15 runners in high school or college, or both. That's a more likely trajectory for a 4:40 frosh wo is a committed runner. The three I know of who broke 4:00 were regarded as amazing talents by the more typical (but still very talented in comparison to an ordinary kid) kids who could run 4:40 as freshmen.
I definitely believe that there are runners who went from 4:40 as frosh to sub 4, but the three I know of personally who got there were much faster that young. All three also were commandingly talented in cross country very early on. After only about 8-10 weeks, the two who were typical age were competitive at the very front of state varsity championship meets and the younger one was by the same age.