People WILL NOT forget about the MAX. Not in the social media & internet age. 10- 15 years ago maybe. not today
The reality is, there are A LOT of MAX orders. Airlines like Ryanair, and most American carriers have 100s of these on order. It will be difficult to avoid also These days cheap short haul is in vogue. Your average traveller isn’t going to go fishing out an a320neo On a legacy carrier when Ryanair is offering a max flight at next to nothing prices like they usually do. most people don’t even check and I’m sure airlines will make MAX flights cheaper to get people on it. Etc
Problem with your theory is the fact that many airlines from Legacy carriers to LCCs uses A320 instead of B737. Some airlines also uses both.
Southwest, WestJet, Aeromexico are the three major airlines in North America who doesn't use A320 family at all. Other than that, majority of them use A320 family.
In Europe, majority of Legacy carrier uses A320 family. Major LCCs like Wizz, EasyJet, Eurowings and Pegasus uses A320 family.
In Asia, the largest airlines (mostly LCCs) use A320 family.
Air Asia, Cebu Pacific, VietJet, Jetstar Asia, Vistara, IndiGo, GoAir, Spring Airlines, Capital Airlines, Citilink.
People would just fly with EasyJet instead of Ryanair since their price and destinations are mostly the same. They don't have to fly BA or AF to avoid MAX.
Airlines are not going to discounted the ticket for flight on MAX plane.