(and yes, the gas engine in this kind of drivetrain will mate to the electric motors during power intensive operations for a boost, but that's not strictly required in this kind of approach)

And, yes, it's a hassle. Life with a pure electric is simple: Plug in at work, plug in at home, plug in at the mall, visit superchargers during trips if needed.

With the BMW's you have extreme electric range anxiety (only 80 miles) if you want to "be electric" and you have to now: plug in at work, plug in at home, go to the gas station by work, go to the gas station by home, plug in at the mall, gas-up by the mall, no superchargers during longer trips, so gas-up frequently due to the 10 gallon (or is it 8?) tank.

Then there's the complexity. You are lugging around 2,000 parts you didn't really want to be lugging around. Is that generator built to last like real auto propulsion engines?

Put it simply: It's a pain in the ass, it is likely to require more maintenance and it is embarrassing.