Remember that "when the ICE is needed" it will require a load on it, most likely both for traction as well as charging the HV battery.

When it first starts up, the ICE runs with almost no load, and you drive on battery power. I think this is a key factor in engine longevity, especially with an ICE that is required to start and stop so often. If the ICE is put under heavy load from a cold dry start, it's not too good for it.