Studi,
The costs of the airbus go up because the interest on the loans made to develope the aircraft continue to accumulate untill you repay those loans. So every day of delay on the claimed 10 billion in development costs = many 10s of millions of dollars in cost over runs, and all those employees are sitting around getting paid as well while no aicraft move out the door.
Of course that only applies for a commercial company and not a state sponsored jobs program that doesn't have to make financial risk benefit decisions before launching a program. Boeing really did bet the whole company on the 747. If it had failed they would have been out of the passenger jet business just like Lockheed and douglas are. Airbus of course will just get the german/french tax payers to foot the bill
Also. The market for the 380 is not nearly has big as you think. The aircraft that killed the 747 was not a bigger aircraft. It was a smaller aircraft. More than two thirds of all 747s sold were sold for the RANGE not capacity. Panam didn't want that LARGE and airplane, they had to accept the aircraft as a byproduct of its range. The 767 killed the 747 on the atlantic, and the the 777 came along and killed it on the pacific.
If you take the 2/3rds of the sales out of the picture that were sold for range instead of capacity than boeing sold only about 400 aircraft over 40 or so years. They would be out of business.
Cheers
Wino