DeSitter:
You know I'm wondering if the 737's shape makes this problem worse. A plane with a mostly circular cross section will be less stiff to the sort of bending moment encountered in turbulence and during landings. The 737's football shape is certainly much more resistant to bending, meaning the energy does not go into deflection, rather, is absorbed internally by the structures.
No it doesn't "make it worse". The fuselage cross section is one of the fundamental design decisions that establishes the performance and economics of an airliner. Furthermore a bending failure due to landing gear loads would have been lateral.
Like this one:
The 737 cross section is exactly the same as the B707 and B727 cross section (probably KC135 as well?), in other words exactly the same as the Thousands of other Boeing jets flying on any given day.
The fuselage failed longitudinally and the tear straps bonded into the structure functioned exactly as they were supposed to - stopping the crack from spreading.
The crack has nothing to do with the "age" of the aircraft and everything to do with the number of pressurisation cycles the fuselage has undergone during its life. We do not yet know if this failure was due to old age, a manufacturing defect, poor maintenance and overhaul procedures or a combination of all Three. Look up the term "hoop stress".