But how often do you have issues with the engine. My last 3 cars never had a single engine issues for at least 175.000 miles. Its very rare today to have big engine issues.
Clearly you're not buying quirky over-engineered German cars loaded with exotic but mostly useless luxury features. They are well built and last forever, but typically require very frequent tinkering to keep them working.
It's the powertrain that's far more apt to be the problem. Hence a plugin hybrid generator style should be far simpler than a system with both an ICE and electric powertrain.
I'm not actually sure how many plug-in hybrids go for an all-electric power train, versus a dual power train.
I know the Chevy Volt had an all-electric power train, and the ICE is purely a generator that dumps power into the electrical system, and the Chrysler Pacifica Hybrid has a dual power train, but I wasn't able to find a concise list of which hybrids have taken what strategy.
parallel versus series hybrid. Series will have ICE generate and the only thing attached to the wheels is electric motors. Parallel (like the prius) the electric motor and the ICE are connected to the wheels. There are reasons for both, but freight trains in the US are series. In my opinion, series is probably the best, since you can engineer the ICE to be as clean and efficient as possible at exactly 1 RPM setting - making them last longer to boot.
I apologize for forgetting the benefits of parallel hybrid systems, but i know there are some, including needing a smaller ICE, all things equal.
For most Toyota hybrids they use a single planetary gear set to combine electric motors and a gas engine into a single unit. That's the entire transmission. It's far more efficient than bolting a generator on an electric car.
For climate control, they are nearly identical to a gas Toyota.
The funniest part is that the way Toyota hybrid powertrains work, if either the ICE or electric motor doesn't work, you cannot go anywhere. It's LESS systemically reliable than either a purely ICE or purely electric powertrain, and yet STILL Toyota hybrids are some of the most reliable cars you can buy.
Their engineering is just that insanely conservative. They just make giant, absurdly understressed engines. You can pull a 2.5L 4cyl engine out of a Camry, designed to make 180 horsepower, replace only a few components, and make 400hp with the reliability you would normally expect from an engine built for endurance racing. They are super popular in drift racing leagues.