We live in a world made up of bell curves and this topic also lives in a bell curve
Automotive OEM's design their products to all kinds of bell curves and this topic is with the ICE bell curve
OEM's has to have enough duty cycle for performance for the worst conditions out there and still perform to specifications. Plus longevity to survive the warranty period(s), plus a bit. Not enough and their product will not live long enough and cost in the service department(s). Too much, and they have left too much on the table to lose money and/or not be price competitive
The ICE is not a stand-alone component/system. There are many other components and sub-systems involved
Tuners play with this ICE bell curve to push it from where the OEM chose (normally the mid point) and pushes it towards the high end, which has less longevity and/or duty cycle