Unfortunately consumers don't have much choice, the airline can change which type operates a flight at any time.

However longer term if Boeing's reputation keeps getting worse that can motivate buying decisions by the airlines. That change will be a very slow one, because fleet changes cost a lot of money in training crews, changing maintenance etc.

For example KLM is changing their short-haul fleet from the 737 NG to the A320neo family, that will take many years to completely roll out.