Next year, there will be four car manufacturers in F1, unless you count the likes of McLaren and Caterham as manufacturers. But do you think there should be more manufacturers or does it even matter?
I think car manufacturers are important for the image of F1. They are brands people care about and are even passionate about. It doesn't make much difference if a team is owned by a car manufacturer or a soft drinks company but more people are interested about the car manufacturer, especially if it's a traditional racing brand.
Also, I think more car manufacturers mean more teams with works engines, that can mean more teams on the top.