Current 737 operators have only placed MAX orders to replace 56.5% of the airplanes in service. This compares with 77% of the A320 family ratio.
The resulting 3,430 airplanes Boeing potentially can sell, when divided equally between 2020 through 2029, comes to 381 airplanes per year. Even at increased production rates to 63/mo in 2020 and 70/mo in 2021, Boeing would not be able to fulfill these orders.
There wouldn’t be surplus production slots until 2024 at this evenly distributed assumption. Realistically, deliveries have to concentrate between 2023 and 2029.
Boeing can’t build 737s fast enough to fulfill the replacement requirement, let alone handle industry growth demand.
737 replacement launch expected once NMA enters service.