They do in South America.
They went nuts in Columbia when Victor Hugo Pena got the yellow jersey. The Columbians I sat next to last weekend at the US Grand Prix saw my US Postal Pro Cycling Team jacket and we had a lengthy conversation about cycling. Monday, I was in the bike shop and had about 20 folks in from Columbia, Guatemala, Mexico, and Brazil and bought up everything we had with Postal or Tour logos.
It is also huge in Mexico. As is mountain biking.
But remember that the Tour is free to spectators and done in July when the entire country of France is on vacation. Would you get 600,000 on d'Huez if they had to pay $75 to $150 (Indy 500 prices) to watch?
For longer events like the Olympics and the World Cup, the Tour is probably third. But it's a very close third.
Indy gets about 300,000 for one day. We also get about 250,000 for the NASCAR race (Brickyard 400), and then topped it off with about 120,000 last weekend at the F1 race. And on top of that, over a four day period draw about 130,000 to the US Nationals NHRA event.