Which leads us to the X5 xDrive 40e we tested in December 2015.
It's rated at 14 miles of electric range, and a combined EPA fuel economy of 24 mpg.
At one point, our driving style must have been sufficiently un-BMW that the SUV showed us 17 miles of available electric range after a full recharge.
Again, though, we didn't get anything close to that.
We noted, by the way, that BMW's displays indicate only "blended" fuel consumption that includes miles covered in all-electric mode, without anything we could find to indicate battery energy consumption in kilowatt-hours.
And several quirks manifested themselves, among them remarkably noisy charging while plugged in, the same lack of AM radio as in the BMW i3 electric car, and no detent in the accelerator travel to indicate the limits of electric-only power.
2017 BMW 740e xDriveEnlarge Photo
We came away thinking that the big, handsome, heavy, $75,000 X5 was a first draft for a much better plug-in hybrid to come.
And that's roughly what our colleague Kirk Bell felt about his time in the $100,000 plug-in hybrid luxury sedan with the cumbersome name of BMW 740e xDrive iPerformance.
He felt his 24.3 mpg was pretty good fuel economy for a car that big with 332 horsepower, one he called "a fabulously comfortable sedan with good power and decent fuel economy."
But, he suggested, "14 miles of range and 111 horsepower [in electric-only mode] won't cut it for most commutes."
This is a car meant to be driven as a hybrid more than an electric car, he concluded, and the electric range really isn't there yet to justify the expense for the plug-in hybrid system.
BMW 5-Series Gran Turismo Power eDrive prototypeEnlarge Photo
Looking to the future, BMW has on tap a second-generation plug-in hybrid system called Power eDrive that it showed on prototype vehicles more than two years ago.
That system uses higher-capacity battery packs and more powerful electric motors, derived from BMW's electric-car development, to provide 40 to 60 miles of all-electric range.
That means that virtually all around-town travel and some significant amount of daily commuting could be done entirely on grid power.
So we'd apply our conclusion about the BMW X5 xDrive 40e plug-in hybrid crossover to this entire group of vehicles from BMW, Mercedes-Benz, Porsche, and Volvo.
They're first drafts of what will be much better—and more electric—plug-in hybrids to come within a few years.
2017 Chevrolet VoltEnlarge Photo
Meanwhile, if you want a plug-in hybrid that offers usable electric range under most circumstances today, your choices are much narrower.
If we set the bar at 25 miles of EPA-rated range, this is your list for the 2017 model year:
Next year, the Hyundai Ioniq Plug-In and Kia Niro Plug-In may join that list, and there will be more entries in years to come.
European luxury makers would do well to keep their eye on that growing list.