So what does Boeing do to resolve future issues with the MAX before this BOT and unassailable expert whisper campaign can do any real damage?
Get it flying again ASAP. Accept the fact that there will be cancelled orders, particularly in less developed countries. The US airlines haven't had any problems with the MAX and have not indicated that they will cancel. Take a hit and offer them unused production capacity from cancellations at a lower price. Get as many MAX airplanes out there as fast as possible and get them flying. The aircraft will have as good a safety record as any other jet. This event will eventually be ancient history and the truth will out. In both accidents, the aircraft was flyable as evidenced by the FIRST Lion Air incident where they just turned off the Stab Trim Cutout and left it off.
Lastly, get out a clean sheet of paper and draw up a completely new single aisle jet aircraft. Get to the cutting edge again, like they did with the 787. Break new ground. The 737 is a GREAT aircraft but all good things come to an end.
Airbus will make huge gains out of this but their production capacity has its limits too. "NEO" or not, the A320 is no longer cutting edge either.
China will probably do well in Asia if it can get its C919 (A320 copycat...kinda) deliveries sped up and uses some of their "belt and road" type financing for buyers. The C919 isn't due for first delivery till sometime in 2021.