This would probably be the concept of democracy (although other candidates would be found in the field of literature): it still has an enormous effect on today's world, in my opinion, making the world a better place (for example: true democracies are more often respecting human rights)
The advantage of an assembly line is that he has to think less aout what needs to be done as it automates the whole process, a disadvantage of the assembly line is that the required output is much higher than it was required of workers in previous periods.
