In early days of the automotive industry there were many auto mfgs who
were assemblers rather than someone who also built their own major
assemblies.

There were companies in business to build just auto engines, others to
build axle assemblies, gearboxes, wheels, etc.

Even today, no mfgs build EVERY part of car.

Seems to me I remember a story that claims that the Seldon group denied
Ford membership because he was an assembler, not a "manufacturer". That
is why he decided to take on the Seldon patent, the book said.