Is this a negative or simply a natural progression. The first exposure of girls to sports was probably basketball. At a time when there was no Title IX, a lot of small towns had girls basketball. Small schools might not have enough money to have a football team, but they had a basketball team. They ended up with a girls basketball team as well.
These kids had no exposure to other sports. There was no golf, tennis, lacrosse, or hockey team in highschool. There was basketball---sometimes track and baseball. Title IX provided more opportunities. But, the nation's youth have now seen more of other sports. More kids may well be playing other sports, and these sports are becoming more available. Club soccer is no longer the only soccer. Some schools concentrate on women's track, and it has its advantages to girls. Running a lot doesn't seem to hurt appearance. But, you need a track coach which not every school has.
I think it is simply more diversity due to more opportunity, and I hope it continues. Since most schools already have a track, seems like a great opportunity for expansion that could affect a lot more players. The distance runners, sprinters, mid-distance runners, weights, and jumpers tend to be different types.