The edge between manufacturers is always very, very thin in cases where manufacturers are actually trying to directly compete with each other. But usually they're not. Cadillac and Audi both build performance sedans but they build them for different demographics, taste profiles and usage patterns and it shows. Cadillac has tried to build cars for Audi customers and Audi has tried to build cars for Cadillac customers and they've both mostly flopped and they've gone back to their own things. The marginal new car buyer who flip flops between brands doesn't really care about that stuff. They have specific and varied criteria they're using to choose.

Everyone on the upper middle class internet shits on FCA because FCA's financing arm has no qualms about writing low end loans which run results in their cars being (when new) driven by people who on average are lower class and less well off than those of the "nicer" brands and FCA consciously builds cars to the price points those buyers want. This results in the cars generally being more clapped out for a given age/mileage on average than "nicer" brands which is then used to justify the shitting-on in a circular logic sort of way.

This phenomena and set of feedback loops isn't specific to cars though. You see it used to justify purchases in all sorts of product classes.