What was the point of striking a century ago in factories in the northeast US when workers in the Midwest and South would work for less? What kept factory owners from shipping factories to the Midwest and South?

Factories could move, but not at the snap of a finger. Union workers made good salaries, and jobs did not disappear from the northeast.

More interesting is Midwest and Southern factories. Midwest factories unionized, North Carolina textile mills did not. Midwest union workers like Larry Page's grandfather, who walked around his factory during a sit-down strike with a hammer to bash scabs and cops - they sent their sons to college with the wages they had, and their grandchildren prospered. North Carolina factory workers did not unionize, made low wages generationally, and the factories moved any way.