You might be interested in the book "White Bread: A Social History of the Store-Bought Loaf" by Aaron Bobrow-Strain

A lot stems from the late 18th century concern that filthy immigrants were making unhealthy food in local bakeries. It was better -- so they said -- to eat mass-produced breads baked into identical loaves with small, evenly distributed air holes by clean machines and in a pure, clean white color to make it clear there weren't any bugs or other impurities.

From there it was a process of mass industrialization and tweaking the ingredients to minimize costs and optimize baking times.