Buying a new car in the United States usually means buying from an independently owned business rather than from the company that built it. The structure is legal as much as commercial, and it is set at state level.
Dealers began as a way to finance distribution
Early manufacturers needed cars distributed nationally without funding a retail network themselves.
Independent dealers supplied the capital, bought vehicles outright, carried the inventory risk and provided local service and parts.
That arrangement let manufacturers concentrate their capital on factories, and it worked because a dealer's investment in a location was substantial and largely irreversible.
State franchise laws made the structure permanent
Dealers who had invested heavily sought protection against a manufacturer opening a competing outlet nearby or terminating a franchise at will.
States responded with franchise laws that restrict termination, govern territory, and in most cases prohibit a manufacturer from selling new vehicles directly to the public.
Because these statutes are state law, the rules differ across the country, and a sales model legal in one state may be prohibited in the next.
The dealer's economics are not what buyers assume
Margin on a new vehicle sale is generally thin. The profitable parts of the business are service, parts, used vehicles, financing and insurance products.
This explains the structure of the buying experience, including the emphasis on financing and add-ons after a price has been agreed.
It also explains why dealers defend franchise protections vigorously, since the service business depends on the franchise that comes with it.
Direct sales models pushed against the rules
Newer manufacturers without an existing dealer network have sought to sell directly, arguing the laws were written to govern a relationship they never entered.
The result is a patchwork, with direct sales permitted, limited or barred depending on the state, and with sales sometimes conducted across a state line or handled as an online order.
Litigation and legislative amendment continue in parallel, and outcomes have varied considerably between states.
Both models have real trade-offs
Independent dealers create price competition between outlets selling the same vehicle, and they provide a local service network with a financial interest in retaining customers.
Direct sales offer consistent pricing and a simpler process, while concentrating service capacity and pricing control in the manufacturer.
Which is preferable depends on whether a buyer values negotiation and local competition or predictability, and the law currently answers that question differently in different places.