Very few hybrids are ever “plugged in”. It would mostly be pointless anyway. They run off petrol or diesel (inefficiently).
The power-trains in top models are excellent for providing a boost to a second set of wheels for massive bursts of power, and claiming bizarre emissions and fuel consumption figures to get around the tax rules, and make their wealthy owners feel happy about their eco-credentials.
Regulators are complicit in this, and follow the money.
But that doesn’t make it right. Modest, lightweight efficient cars with modern efficient clean ICE power, suited to the size, and driving rules and speeds, are much more important, and fortunately very available.
Two or three ton (hybrid) trucks to take the kids to school, or bomb down the motorway at x2 the speed limit, don’t interest me. Nor supercars with a hybrid system to play the regulations, instead of a massive engine (they mostly have this too).
What I’d like to see is a ‘hybrid’ gas (or diesel) and electric car that only uses the electric motor for acceleration boost. IMHO, that’s a good, legitimate use for an electric motor. Gas engines suck a lot of fuel to accelerate, and not as much to maintain speed on flat ground.
The battery should be charged mostly by regenerative braking and from putting a load on the wheels while rolling downhill during normal driving.
It is also used, to some extent, in ordinary cars which have “smart” alternators which boost their output when braking, and reduce it under steady operation, meaning much of the electricity demand of the car is supplied by regenerated energy. It’s hard on the battery though, which is mostly operated at less than full charge, (leaving spare capacity for the regenerated energy) particularly when engine stop-start is activated as well. Expensive AGM lead batteries are necessary.