One of the world's most complex engineering challenges, filled with tens of thousands of highly engineered parts and tens of millions of lines of code, with per unit pricing ranging from $10k to $100k+, is a "commodity"?
The term "commodity" typically refers to products that feature little to no differentiation between each other. It means you could largely "throw a dart" to pick one, and you'd be no better or worse off than someone who does meticulous research.
That you say you won't buy another car until yours falls apart already suggests that perhaps you don't actually consider cars to be a commodity. Sure, you won't upgrade in order to get a faster or more luxurious car. But I'd imaging from your statement that reliability is probably important for you. Although you don't state it, if you frequently have family with you in the car, or even if you don't, there's a good chance safety is important as well. Cars from various manufacturers vary greatly in both these respects.
Not to mention that for other people, sportiness, luxuriousness, ruggedness, storage space, and other factors are important as well, and cars vary on those dimensions as well.
If the vehicle market qualifies as a commodity, so are the majority of markets of any sort, to the degree that the concept of a commodity adopts a useless definition.