[InclinedPlane]

Not really. In this case the commodity is transportation. What are modes of transportation? Walking, bikes, trains, buses, and personal automobiles (among some others). In New York City the automobile industry doesn't have a monopoly on daily transportation needs, millions of people take the subway every day. In Amsterdam transportation needs are partly met by people who ride their bikes a total of 2 million passenger-kilometers on an average day. Similarly, walking is a bigger share of daily travel needs in pedestrian friendly cities than it is in many automobile focused cities.

That is an important point, especially in the 20th century, because the common nature of the automobile naturally leads all automakers towards sharing common cause on certain big issues (like road building and use; parking availability and cost; petroleum production, use, and taxation; land use; and so on), many of which differ strongly from the desires tied to other ways of meeting transportation needs or of the public at large. "Monopoly" is the wrong term, but oligopoly is accurate, and equally concerning.