The reason might rather be that it doesn't make sense to purchase an aircraft passengers are reluctant to fly with. No matter how well the problems of the 737 8 MAX are resolved, its reputation is tainted. Every further accident of that type will be blamed to Boeing.
It reminds me a lot of the DC-10 in the 1970s.
Boeing will probably have to rename the 737 8 MAX and marketing it as a brand new type.
I'm pretty sure the percentage of travelers who check the type of aircraft an airline uses before booking is counted in some small fraction of a percent. I surely never did, and never heard anyone mention they did.
Also, Boeing is not going to fool any airline by simply re-branding the plane, so if airlines pressure them now to get discounts on their 737 MAX 8 orders, that obviously also applies to the rebranded plane.