I think Spain must be doing something better than France because Spain has managed to produce one great champion - Nadal - and several other very good players, including major winners, though "only" on clay and mostly in the men's game.
As someone pointed before, Nadal is not a product of the Spain's tennis academies system. The Spanish system is obviously very good if not the best in the world right now, but Nadal has nothing to do with it. He's a standalone phenomenon.
Also, academies can produce good players, but the all time greats require special some random individual traits, not only good academies.
Sorry for the offtopic but:
USA won the gold in the 2008 Olympics and the 2010 FIBA World Championship
You have to admit that the gap between the USA and the rest of the world has become smaller. Some time ago, it was unthinkable that any national team could defy an USA professional team. Right now, Spain and Argentina for example can defy the USA and they even succeeded at some point.
Also, there was a time when it was unthinkable a Spaniard like Gasol, formed in the Spain's system, could be playing in the Lakers' starting five and being the sidekick of a dominant superstar like Kobe Bryant. No one in Spain could imagine that, 20 years ago. It was simply not possible. In fact, it was unthinkable that someone from Spain could be the leader even in a smaller team like Memphis.
I agree with who said American basketball has become slighty duller. NBA is still the undisputed world basketball's Mecca, but guys from many other countries are catching up. Every expert's list agree in their NBA's current best players lists: always a significative number of foreigners among the top players. Think about it. Basketball was a pure USA sport like baseball or NFL are. With the difference that the rest of the world actually liked it (unlike NFL and baseball who are deadly boring to most foreigners) and the world started playing it even with no hopes of winning. It was science-fiction thinking that the world could catch up with the USA in their own American game. But it's happening, to some extent at least.
If that happened with basketball, an American game, it's no wonder it could happen with tennis, which is an European game and has a lot of tradition in many countries.