Not information just a random thought, the older generation got to the sport as teenagers, this generation is already practicing as little kids. I think this has a lot of impact in the results, and as gymnastics this children's are able to twist there body's in a way that with age the pain is unbearable.  

 I got my first skateboard in 1977. I was 7. So I think you've skipped about 4 generations.  

 When i was kid in the 90's i would say that 99% where boys, today i see a lot more girls with a skate