I think you missed the point. If turning on the cabin heat turns on the ICE to create waste heat, then that PHEV has 0 pure-EV range at any temperature below 60 degrees (15 C).
No. My point was that the range of a PHEV is essential fixed, based on battery capacity and fuel capacity. Nothing extends either the EV or HV range. In my opinion, “range extended” is a nonsensical term.
What you are saying is that in some vehicles, the climate control system triggers the ICE, thereby preventing the driver from operating the car in EV mode. That just means the car is using gasoline to heat the cabin and propel the car rather than using electricity to heat the cabin and propel the car. Either method will reduce range.