No luxury does not mean seating for 4 but that sure helps. One of the main things a luxury car needs is a very comfortable ride which I kind of doubt the Veyron has. When you look up a listing for a Veyron it is described as a "sports car" not as a luxury car, I would imagine that it has a stiff ride and not all that comfortable to ride in, especially when you have to stop for gas every few minutes
In the end it doesn't matter if they call it luxury or not, it is simply a big, heavy, poor handling, very fast in a straight line, very expensive eye sore