What was the introduction of the assembly line crucial to the success of the model T?

Henry Ford did not invent the assembly line but he did improve on it. The assembly line helped the motor vehicle companies produce many vehicles in less time allowing the finished product to be more affordable to the general public.

Oldsmobile mass produced the Curved Dash Olds on an assembly line from 1901 to 1907 producing over 19,000 vehicles. Henry Ford's Model T was introduced in 1908.