These things go in cycles, (no pun), 25 years ago we had no sprinters and world class middle distance athletes, 10 years ago we couldn’t move for guys getting to the 100, 200,and 400 final.
With XC, well 20 years ago with Baker, Gould etc, there was only XC to speak of so all the talent went there. Now we XC, marathon, 4X, downhill, and most likely around the same size pool to recruit from.