56 million cars sold last year. How many do you think were bought because they do not create emissions, or because of any serious consideration of the engineering behind them?
People buy a Toyota Corolla or Prius because it's below the median price, reliable and efficient. They will buy it and then never think about it again because it'll "just work."
People buy a Ford F150 because they either have some real use for a full-sized truck or, as we know is often the case, they want to feel like they are in the "big" vehicle, the "fancy" but "powerful" looking truck.
People buy a Porsche 911 because it's a symbol for having the money to throw at a fun, slightly exotic machine.
People buy a Tesla because it's a symbol of embracing the future, seeing cars as technology, and freeing them from generating exhaust and visiting gas stations.
People buy a Honda CR-V because it can do enough things well that they can just use it, fit people and stuff inside, feel safer when it snows, and so on.
People buy a Kia Soul because it's a little off the beaten path and comes in crazy colors.
Obviously the exact reasons behind each car purchase vary a little per person, but that's kind of the point. People want a car that feels like "them", and has enough practical use to justify their decision.
Automotive maker consolidation isn't new, just like any other industry, and it certainly would leave many unhappy if the options narrowed severely, because there are different use cases and preferences out there. For now, the market is so big that Toyota can have 6 different SUVs that are all slightly different, and you can configure a Ford F150 about a million different ways. (Though with colors converging back on black, white and gray, we're nearly back to the days of "You can have it any color, as long as it is black."