It’s more than simple profit. To build the 380, Airbus had to learn to create carbon fiber wings - the largest wings ever attempted out of carbon fiber. When they did this, they learned things that they didn’t know before. This knowledge will carry over to other designs.
If you can make the wings of the 380 out of carbon fiber, you can make other wings for other aircraft using a similar process. This makes future designs more cost effective.
That is progress. If all you do is re-hash an existing design; you are not learning. That is where I’m holding Boeing up to task for. Airbus invested and risked a great deal to develop this aircraft. The lessons learned will make other aircraft better - without having to re-invent the wheel.
Wing roots are the biggest challenge in these huge planes. C-5’s have been flying for decades with “acceptable levels” of cracks in the wing roots. If the carbon fiber works, that would indeed be a big advance.
If I recall correctly, the technology for constructing large aircraft out of carbon fiber was developed in the US for the B-2 bomber. Boeing's 787 used this method long before Airbus.
Like I said, Airbus is a jobs program. Take away backing by the european taxpayers and Airbus would have gone out of business 30 years ago. They do a fair job of constructing aircraft using technology developed here over the last 50 years, but that's all.