I attribute this mostly to not having much extraneous lateral force when I'm cutting.
This is the crux of the problem. I believe that most large chips, outside of dropping and banging knives into sinks or during shipping, happen from bad technique, lateral and twisting forces. I have no way of proving it though.
I dont have many data points (at all)... But my limited experience (and gut hunch) is that kitchen knives that are 'fragile' on paper, can still be reliable if used right.
I am willing to treat this null result as an 'evidence of absence' sort of thing....(the knife is not chipping or rolling so it is 'tough')... That said, I am not willing to deliberately disproof the prove the point by introducing negative evidence
I have no way of proving it though.
But logical arguments can be appealing! Force vectors that occur on the plane running through the middle of the blade can distribute strain throughout the body of the knife. This means the stress in the material can be spread over a larger volume. Forces that act off this plane have less supporting material to absorb the energy. The worse case would be applying a force laterally/perpendicular to the very edge.... there is little material to support this strain. The internal stress becomes very large and can quickly exceed the yield strength or ultimate tensile strength of the material.
I think this is roughly correct ... could be wrong...