Excellent point, Heinkel. You also have to remember that the TdF, the big showcase of cycling, was forced to go international in the 70s whereas the Vuelta and the Giro have stayed pretty much Spanish and Italian races respectively, giving home riders much greater opportunity to gain experience at GT level.
And it's quite true that most French kids would rather play football or basketball than get out and ride a bike
Another possibility could be that the French media has such a desire to see a true contender, that the pressure to perform could be overwhelming. Here in the USA, New York's media is such a circus when it comesto their teams, the athletes either thrive or fail miserable because they can't handle the pressure. I dont live in France, so I can't speak for if this the exact reason, but I imagine it has affect. HInault had the personality to handle it.
Every sport and/or country wants to the duplication if its heros. Example, IN Basketball, the media has been dying to see another Michael Jordan, and every kid for the past 20 years when he shows promise has been labeled the "next MJ", and it took quite a while to find one that can be in (Kobe Bryant). Such is France wanting another Hinault, Belgium wanting another Eddy, Spain wanting another Indurain, and the US wanting another Armstrong.
I remember Moreau and Virenque were both suppose to be the next TDF winner, and Virenque managed to podium, but Moreau never lived up to the hype. Someone will eventual come along and take the mantle, just need to give it time to work itself out.