Also, maybe to add to that, the Dreamliner was a new design, of which apparently even considering some setbacks along the way Boeing was still capable of at that point in time.

For the 737 Max, they were very late and had to react to Airbus much better neo offering, and didn't have the time and/or money and/or capabilities to develop a new airplane, so a lot of in the end deadly compromises had to be made to somehow bypass training and security certification as much as possible using the old airframe at low cost.