If you look closely at some of the edges between the car and the background, there are features that makes me suspect that the cars were shot in a studio and placed in the background in photoshop. In any case, I don't think using a polarizer alone is enough to achieve zero reflections. The cars are not matte finish in real life, but it seemed that the photographer deliberately makes them look so. There's definitely a lot of photoshop work involved.
To me, reflections are what makes a photo look natural. Some reflections are too messy and photoshop is needed to tidy them up. Even with matte finish, there will still be reflections, just not as defined as cars with gloss finish.
In CG, render artists spend a great deal of time creating HDRI environments so that it can create a realistic looking render that involves the right lighting and reflection simulation. Shots like these look like the days when HDRI technology was still rather crude.