> The "cushiness" of jobs such as fewer work hours, more benefits, etc. preceded the formation of unions and then slowed down (overall) once unions became popular.

is demonstrably false.

Sure, unions are not the only reason for better working conditions, but they certainly played a very important role.

The legal restrictions on the max. number of hours people are allowed to work per day or week are only in place because of the worker's movement and the power of unions. Companies certainly didn't lobby for these laws. In fact, certain industries are constantly trying to soften or undermine it.

BTW, in my country, unions are part of the annual negotations between employers and employees ("Kollektivvertrag"), which most notably includes the minimum wages and annual pay raises.