It looks like those 800 planes should be scrapped and a clean sheet plane should be designed.
If they could, they would. At this point, the MAX might be a civilian equivalent to the F-35 in that it's now too big to fail.
I've also used this same analogy recently, but am not sure it's a great fit.
The F-35 was built to governmental specifications (US and partners) and with government money. I think it's fair to say that it is a national imperative of the US and the F35 partner nations. The program has encompassed the defense industries and government labs so intensely there really is/was no viable Plan B. The fall back to an earlier generation of designs is not viable, the adversaries have made their own advancements in the decades of development and the older designs are very limited in their usefulness.
MAX was built to commercial specifications (Boeing and partners) with commercial funding (I'm intentionally not going down the subsidy rat hole, it adds nothing to this specific discussion IMO). I think MAX is economically significant to the nations that host Boeing and its partners, but I would not say it is a national imperative.
Banks were too big to fail because if the world financial system was taken down life as we know it would take a big hit. A constricted aviation system is a problem, but nothing as big as no longer being able to use money.
If MAX never flies again, Boeing and its partners take a HUGE hit, but life as we know it goes on. Air travel gets scaled back. The value of used NG goes up even more than it has. A lot of CFM56 engines get rebuilds. The system would adjust. Presumably Boeing would come up with a replacement, but IMO even that isn't an absolute requirement. Some other player or combination of players would fill the void. As suggested earlier in this thread maybe Boeing does use such a scenario to beg the USG to underwrite a total reboot of BCA, but LM and others would have something to say about that. Point is, air travelers would take a hit, but life in general would go on.
MAX is only too big to fail when you look at it from a Boeing Commercial Airplanes point of view, and one could even make an argument they may be able to get by via just selling their other airliner and freighter products after a big restructure.
This doesn't contradict earlier things I've posted. Boeing's interests are by far best served IMO by doing everything they can do to get MAX back in service. Whatever problems that involves are much smaller problems than the ones created by dumping MAX and figuring out what to do next after you've burned all the MAX partners and all the MAX customers by dumping MAX.