I wish FR had an edit button. The engine only kicks in when the battery is depleted but does not directly power the car. It recharges the battery which powers the electric motor that drives the car.
That’s probably what needs to be done in order to sell more hybrids, optimizing the relationship between burning fuel and using the battery, refining it to a point where there is a seamless change between burning gasoline and using the battery where the driver isn’t having to think about it. It just happens.