Why is high school track stuck in the past?

[Halfmiler2]

Peter Snell ran his first sub-4:00 mile and first WR mile (one and the same!) on a 385 yard grass track in NZ!!

1500?
1600?
400/440 tracks?
500 meter tracks?

Explain a 385 yard track!!
Or for that matter, a 146.7 yard indoor track the Millrose used their entire history (until this year!).

Maybe the 385 yard track was meant to be the finish of a marathon course.

The Millrose track that was 11 laps to 1600 meters was only used the last decade or so. Before that, the track was 160 yards.