And if it is a success, then the airports will make the improvements or the airlines will pay for improvements to use it there.
If it turns into a big flop, or an aircraft that is only used on a few markets with severe slot constraints, then most will not.
Is Airbus an aircraft manufacturer? Or a religion?
Why does everybody get so excited about things like this? Nobody is being insulted if there is something better or worse between Boeing and Airbus. I have flown both and both had their faults and great features.
Remember too, the 747 became a success in far different market conditions (cheaper fuel and regulated air travel) and had far fewer competitors. The success of the 747 against the 777 in the long haul pasenger market now days isn't that good either. Airlines prefer to offer more frequency if possible and they are concerned about the fuel bill.