This has proven very difficult to predict, but would say probably no one who did not run 1:49/4:03 the year before or some similar combination. I think athletes like, Lingren, Hunt, Pre, Hall, Rupp, Ritz, Magness, etc., didn't go sub-4 becasue they did not have any 800m credentials, but Danielson and Verzbicas proves that's wrong.
The only thing I can see that all of the sub-4 guys had in common was great coaching, which is something no one ever talks about. Even exceptional H.S. coaches who have produced 4:10 milers are out of their league when it comes to the planning, training and mental prep for 3:59.