Why is it that as soon as an attraction closes or is slated to be closed that we immediately try to replace it with a new movie themed ride or attraction? American Idol is closing, let's make something Star Wars. Let's make a new land based on Avatar. We have to have a Cars Land.
Disney World's classic attractions for the most part had nothing to do with movies. Horizons, Spaceship Earth (original), Soarin, Pirates (yes, it was a ride first), Space Mountain. You get the idea. Most modern movies don't have the staying power of the original classics like Snow White (even though they closed this icon), Peter Pan and new classics Beauty and the Beast, Little Mermaid and Lion King.
Don't rush out to build new lands on not so classic movies. Nobody will care about Cars in 2 years. I don't care now.
Your arguments aren't very solid. (Please don't take this personally, I am only commenting on an argument that I see over and over again here.)
It seems that most people that make this argument aren't very familiar with Disney history beyond the feature length cartoons. While some original
Disneyland attractions were based on either movies (Snow White, Peter Pan) many werre based on concepts behind Disney's live action material.
Some examples:
20,000 leagues Under the Sea after the movie
Frontierland based on the smash TV hit of Davy Crockett
Pirates of the Carribean was based off of the hit film Treasure Island
Adventureland was originally going to be called True Life Adventureland after Walt's series of True Life Adventures
Swiss Family Treehouse was a movie
There are a few things that aren't (It's a Small World really sprang out of the World's Fair, as did Carousel of Progress. Haunted Mansion and Space Mountain were very original concepts.) but Disney has ALWAYS based their theme park stuff on existing properties, just not ALL of it. The reason they are more likely to now is the expense. Attractions cost $200-$500 million, and they are very risk averse to put out something that is not immediately popular. (The flop of Mission:Space may well be the last time you see them take that chance - and that wasn't even really a wholly original property either.)
In addition you are complaining about replacing old things with new things - yet you don't like the idea of them closing American Idol (which is 11 years old) and replacing it with Star Wars (which is 35 years old), which is in fact the exact opposite of what you are arguing against. Avatar is the closest thing to "too new a product", but they are not even closing anything to put it in. (They moved Festival of the Lion King, and Pocahantas and her forest friends closed long before Avatar was in the wind.)
Finally you claim "no-one will care about Cars in 2 years". You do realize that Cars has been around 7 years and it continues to sell a billion dollars in merchandise every year, and almost every boy between 2 and 8 is in love with it. It's Disney's second biggest merchandise seller (after the Princess line) and Cars hasn't even reached the 2nd generation point yet. (The point where the parents grew up with it, and now are passing it onto their kids.) This is where Little Mermaid and Toy Story are at now. You are rights, Cars is not a great movie, but it is hugely popular. The fact that they are producing spin-off product (Planes, rumored Trains) means it's unlikely to go anywhere soon.
In the end, regardless what you are trying to point out, I'll also argue that what the ride is based on doesn't matter as long as the quality of the ride is there. Have you been to DCA and ridden RSR? I am not a huge Cars fan (who over 8 is?) but that is the best ride that Disney has produced in 25 years. It is amazing and wonderful and clever and fun. Carsland itself is very impressive as well. I for one am a little sad to hear they are now thinking of NOT bringing it to Florida, though if they don't I would applaud the choice to leave DLR and WDW more unique from eachother. I could care less what Disney does next, Star Wars, Marvel, Lord of The Rings, Avatar....if they put that much care and quality into the product as they did with the recent DCA re-do, I'll gladly enjoy it.