Normalizing for the cost of fuel, the BMW costs 9.19 cents per mile. The Prius costs 7.81 cents per mile. That is based on your MPG figures and the current cost of fuel in my town today. 85 octane gas at $3.13. Diesel at $3.85. The Prius still wins on lower initial cost of acquisition and lower cost of fuel. As a former owner of a couple Porsche cars and a Toyota pickup, I'll lay bets that the maintenance costs for the BMW (parts & labor) will be much higher than the Toyota product. A fine German car is a joy to drive, but you really have to be prepared to pony up the $$$ for maintenance to keep it that way.
Hybrids do shine IF they are driven in city conditions in relatively nice weather. Once the temperature extremes require use of the heater or air conditioner, the advantage is lost in the need to operate the internal combustion engine to provide the heating or cooling. The Prius driver knew enough to avoid using either in the story. The BMW driver opted for comfort as there is only a small penalty for a vehicle that has to run the internal combustion engine full time anyway. My 2008 Mariner Hybrid can achieve 32 MPG in mild weather and city conditions. On the road it will average 28 MPG. Winter temperatures can drop the MPG to as low as 21.8 MPG. As Spring is approaching, our long term average is running around 25.7 MPG.
Fuel prices are variable. Six months ago, diesel was cheaper than regular unleaded gasoline. Currently, cheapest regular unleaded in the Portland, Oregon area is 3.29; the cheapest diesel fuel is 3.83.
Furthermore, they intentionally compared apples and oranges here. A big sedan vs. a smaller hybrid sedan.
If you compared a 118d versus a Prius, you would see an even larger mpg difference.
While gasoline/electric hybrids aren’t really very efficient on the highway, they are a good fit for someone who drives primarily in congested areas, or for delivery vehicles.
What is going to be interesting is the Chevy Volt, which GM is calling an EREV (Extended Range Electric Vehicle). It will be most efficient in the same applications as hybrids, but will be able to be used without running the engine for a 40 mile range. And the engine only recharges the batteries; it does not drive the wheels.
BTW, I wouldn’t be so sure about the maintenance being cheaper on the Toyota. Their quality is tanking, as they’re ramping up to try to overtake other automakers.