The start of the MAX-8 & -9 problem is the "Leap Engines", they are larger and required the engine to be moved forward and higher compared to the previous model. This put the thrust centerline forward an higher, which in certain conditions will cause the A/C to pitch nose up. The best way to correct this is with a longer landing gear and leave the engine in its proper location.
the cost to making the gear longer, was to Boeing prohibitive, both the wing and fuselage would have to be redesigned as well as all the ground equipment to support such an aircraft.
When one understands Boeing's philosophy of grandfathering new model aircraft from the previous ones you will see how this drastically cuts cost, look at the shape of the cockpit widows, they are basically the same as the first 707, cockpit instrument panel layout has taken Boeing a long time to come into the modern glass cockpit due to this as well.
The Cost of the A/C, crew training, spare parts and part commonality all play into this for a cheaper product to the airlines.
But this one has gone to far and Boeing AND the FAA will pay for this in the long run.
The winners in this will be Airbus and the new Russian MC21