There has always been a penalty for being first in airliners, because the second one can do it better. And Boeing has been the victim of this more than once. First, they came out with the first modern all-metal airliner, the 247, only to be completely outclassed by the DC-2. Then the Stratoliner was upstaged by the DC-4. The Stratocruiser was never upstaged, it was just too expensive and unreliable. But Boeing only just escaped being upstaged when the DC-8 came out at 6 abreast when the 707 was going to be 5 abreast. The decision to redo the 707 was one of the gutsiest in industrial history, as up to that point Boeing had never had a successful civilian plane, and they were already producing the KC-135 with the narrower fuselage and a production run that was only supposed to be for 29 planes-the rest were to be Lockheeds. So it was an enormous gamble for them to make the 707 different.
The 737 was designed to be as low to the ground as possible for speedy loading and unloading, as jetways did not exist at that time. It did serve its purpose well, but was competing against the DC-9 as well as others that have disappeared. In the 80s the Classic came out, which was a huge improvement. But it was still hampered by the low landing gear. Then the A320 appeared about 5 years later, and was clearly superior. Boeing was doing the 744 at the time, and preparing to do the 777. They probably did not take the A320 seriously at the time, and did not until they started losing domestic orders to it. Had they jumped sooner they could have come out with a new plane, but at this point felt that updating the 737 again was their best choice. And they did a superb job; according to all I have read and according to the sales results, the 737NG and the A320 were extremely close in performance.
But then Airbus came out with the NEO, and the short landing gear of the 737 made it impossible for Boeing to pull another rabbit out of the 737 hat. And the customers were not willing to wait for a new aircraft. They came out with the MAX, which even without the MCAS problems was not the equal of the NEO the way the NG was to the original A320. So Boeing is now between a rock and a hard place; the problem all along is that they have not had technology to improve the economics of the new plane enough to justify the expense of a new plane. But the MAX debacle may force them to do it. They missed their best chance which was when the A320 first came out. But they thought at that time their main competition was the MD-80.
I like the history. I too suspect that Boing has reached the end of the line in terms of economics with the 737. Their next move should be a clean sheet. If Airbus is smart (and I think they are) they will eat their young and introduce a clean sheet as well.
The business case for Airbus to do a clean sheet replacement of the A320 is much less compelling. What can they do to improve? CFRP technology does not give the benefits on a narrowbody that it does on a wide body, at least at this point. Boeing will probably use it on the NSA, and we will see what they come up with. However, if Boeing succeeds with it, and is able to bring manufacturing costs down so that they can have a price advantage, that will give Airbus a reason. It is not certain, though, that it will. It may lower maintenance costs, but whether or not that will be enough to tip the balance is uncertain. But right now Boeing needs to do it just to stay in the game. Airbus doesn’t yet.
The A320 sold well as it brought technologies that improved, but do not assume their aren't technologies out there that cannot be retrofitted:
1. Electrical subsystems. About a 3% fuel burn savings despite a ton increase in weight.
2. CFRP wing. Reduces weight, alliws easier underside laminar flow, and practically immune to wear and tear if the impact sacrificial layers are done right. There is a reason the 787 is certified for more cycles than the A220 and more hours than any other commercial aircraft. About a 3% drop in fuel burn at a $2 billion cost.
3. Folding wingtips to add even more underside laminar flow. Another 3%.
Then the way the nacelle anti ice isn't as durable as all electric subsystems. While at it, the new gearbox would drop fuel burn 3.5%, but needs taller gear.
The A321 has the wrong winv. Seriously, a wing optimized for 75 minute missions flying TATL?!? I can do it, but a proper wingspan would not only reduce the above 3%, but another 4% just by getting up in thinner air (less drag).
However, Airbus should focus on automating A320 production and reducing cost. At this time Airbus controls the more technologically advanced competition that needs production help, PiPs, part support, and needed direly more orders pre-Airbus.
So the A320 is safe for now. Don't pretend better isn't available. But is there a business case, with how well the A320 sells, to invest $9 billion in a new aircraft and $5 billion in new factory automation or automate A320 production?
For myself, the answer is easy, automate A320.
Winter is coming.