What would really impress would be if they now ordered 49 COMAC C919 narrowbodies from China. That would send a signal that airlines are fed up with the A-B duopoly and that they're not prepared to take recycled designs any longer.
I believe that the use of recycled designs is one of the major guarantees for aircraft safety! There is nothing wrong with a gradual development process, where only small modifications are done from one revision to the next. This is a bit like continuous integration principles in software development. Building on former experience as much as possible is an important factor of quality assurance (and also efficient in many other aspects).
I understand your point, though: small modifications can sum up to a point, where they do not blend smoothly in the base design anymore - as is the case with the larger engines of the 737 8 max. At some point, designers have to refactor big.
What went (criminally) wrong with the 737 8 max, in my eyes, is the attempt to treat a large redesign as a small modification, to save (certification) time and money. It went horribly wrong, causing loss of lives and trust in the company.
And obviously Boeing is not able to understand the consequences of the loss of trust. Last week I thought, the worst thing that Boeing could do now, was to offer quick fixes (like hot patches for the software), as this would proof their incapacity to embrace the scale of the problem. But this is exactly what happened.
(though the issue here appears to have been Boeing didn't recycle enough of the previous generation 737...)
The reason might rather be that it doesn't make sense to purchase an aircraft passengers are reluctant to fly with. No matter how well the problems of the 737 8 MAX are resolved, its reputation is tainted. Every further accident of that type will be blamed to Boeing.
It reminds me a lot of the DC-10 in the 1970s.
Boeing will probably have to rename the 737 8 MAX and marketing it as a brand new type.
I'm pretty sure the percentage of travelers who check the type of aircraft an airline uses before booking is counted in some small fraction of a percent. I surely never did, and never heard anyone mention they did.
Also, Boeing is not going to fool any airline by simply re-branding the plane, so if airlines pressure them now to get discounts on their 737 MAX 8 orders, that obviously also applies to the rebranded plane.