I dont think people will all of a sudden start ditching cheap flights just to avoid the max or Boeing. Airline industry is extremely price sensitive from a consumer perspective, and for people to potentially sacrifice hundreds of dollars of savings would be a non sequitur.

For example, if airline A flies MAX and has a ticket for 200 and another airline B has the same route for 400 on A320, most people I know would still fly the MAX because they cant afford to be picky.

I think talking with your wallet works only when the price is relatively inelastic