Very good points about calibration and soundstage. Automobiles inherently struggle with this as it is, adding more drivers in different locations only exasperates the issue. Also, if they use a 2-way design, the count that as 4 speaker. 3-way designs counted as six speakers. Plus, peak watts from the amp are advertised.This. Very few of the "premium" systems anymore are actually premium...just licensed names on garbage components. A recent example is the "Bang and Olufsen" systems in the Ford...atrocious in actual ability to create quality sound because it's a name tacked onto garbage. The name of the game now is see how many dozens of speakers we can put into a car, as quantity sells better than quality. For music, all this does is complicate the sound stage and makes it even more difficult to actually calibrate a system properly.
The average car shopper nowadays uses the internet to determine which vehicle they buy, and for a lot of them, it is a numbers game. They want the most horsepower, the most number of transmission gears, the lowest 0-60, the highest skidpad, the most speakers and wattage, etc. The car could actually drive like complete crap, but they're happy, because they got the "best".
There is so (and I cant stress this enough) so much more to a driving experience, and listening experience, than what the numbers tell you.