There are some issues tied to it. Usually a car purchase has a lot more depending on it. It's not really like buying a phone, you can walk up to the next store and get whatever you want or just walk away without any major impact on your day to day life. Unless you live in a large urban center, you kind of need a car as your primary means of transport.
For example, selling your old car or maybe even being without a car for a while. Now the car you ordered is not the way you want, you're cornered into making a decision. On top of that, just to go pick your car up you'll need to have your bank draft, insurance etc. all set up only to find things are missing from the car. A lot of wasted time and effort. So yes technically "it's a choice" but I would say mentally you had committed to the car the moment you filled out the finance application or insurance info. Not really comparable to any typical product off the shelf.