If you think that everyone who knows more than you about how engines work is from the auto industry, then that would be just about everyone else here. I have no affiliation, just a lot of time working under hoods.

Lets see, you were wrong about mixtures, Prius acceleration, the 5-10% advantage, complexity, and the OPEL example. Does that help?

You said "the effort of a diesel is only worth it for a heavy car"
That makes no sense when it is only as complex as a gasoline engine, and drastically simpler than a hybrid drivetrain.

First, we're not going on the rumors. Only what exists. Show me a test of the Prius done this year that confirms 70-100 mpg.

The Golf TDI Hybrid exists. It has been tested, and it gets 26% better mileage than the Prius.

Whatever a gas hybrid can do, a diesel hybrid can do 20-30% better.

Plug-ins are another matter. Over half of the US power grid is supplied by fossil fuels, which average just shy of 1kg CO2/kWh. So on average, plug-in users will be forcing the use of 500 gCO2/kWh. The plug-in Prius will have a 2.6kWh battery. So About 1.2 kg CO2 for a full charge. That full charge will carry it 8km. That is 150g/km C02.

And all my calculations were modest. Its actually much worse than that, but I'll give the benefit of the doubt.

So electricity from your wall, while much cheaper, is actually polluting more than a VW Jetta diesel. A mid-sized car with no hybrid drivetrain.