I think a lot of it has to do with the US college system and the perception that the steeplechase causes more injuries. Most of the best US runners go to schools that compete for team titles. Even if someone is good enough that they could win the steeplechase, coaches do not want to risk injuring them and having them miss out on team championships, so they put them in the 1500, 5k, or 10k. They figure its better to have a guy who could be, say, 3rd, in one of those events than injured and not competing. They would rather have a lower risk with lower return.
By contrast, in Kenya, where most of the top steeplers are from, coaches are most concerned with fast individual times and finishes, and they feel that if a certain athlete would do best in the steeple, it is worth the risk of injury.
However, I am not a college coach, and I have never talked to a Kenyan coach, so I could be wrong.