airbus double decker

Im of the opinion that this airliner is going to be a flop,heres why:People dont realize that airliners are designed on a razors edge of a balance between many factors,you cant just enlarge the fuselage and put in a whole new floor of seats.This new floor will require a strengthened fuselage which will be heavier,requireing bigger engines and more fuel,which will in turn require more strengthening and larger wings,etc,etc.This cycle wont end until your left with double the fuel burn negating any economic advantage of double passanger capacity.The takeoff run will end up being so long as no current airport can haddle it.The only way around all this is to take some totally new design approaches.Im not going to say what I think these approaches should be because as I said in another thread,I think its time we get paid for our ideas.