The real secret of the American model isn’t a Ranch in Texas. It’s the HUGE base. Thousands of clubs. Tens of thousands of competitive gymnasts. A fantastic Collegiate competitive program.
Aimee linked to this excellent article – Aimee Boorman, Simone Biles’ Coach: 5 Fast Facts You Need to Know
If you have a big enough program, superstars like Simone and Shawn will have a chance to be identified at a young age.
Gymnastics Coaching.com 
I’m not quite so sure about the size allowing discovery at a young age.
I think a key aspect of the US program is that even if you AREN’T discovered at a young age, you can continue in the sport.
LikeLike