Just like Steve thought my 2G was too old to get 4.0....so you are correct
Thats not as valid an argument as you want it to be. iPhone 2G (and all other iPhones) got two MAJOR versions of iPhone OS updates (and everything in between) i.e. the phone was supported throughout the length of a 24 month contract. Ditto for the 3GS (iOS 4&5).
Majority of Android devices get ONE major update (if its a flagship) and then you have to buy a new phone to get anything more.