It would seem they're neglecting the elephant in the room:

The average millennial doesn't have much disposable income.

Sure, it's not all of them. But many of them are struggling financially, and a new car, no matter how "cool", "hip", or whatever the current terms is, just isn't something they can afford. So they drive old cars, and drive them less. Or they live places they don't need cars.

You can stick $10k worth of the latest and greatest gadgets into the new car, and all it will do, at best, is end up as their phone background (the equivalent of my generation's poster on the wall), and move that car $10k+ farther away from what they can afford.