Technological advancements and globalization didn't all of a sudden happen overnight in the mid 70's, your explanation doesn't account for the sudden transfer of economic growth that took place in ~1978 and it certainly doesn't justify it. Nor does it account for the dramatic increase in top executive income (from ~25x's the average worker's income in 1970 to ~325x's the average worker's income in 2015). It's clear to anyone who reads the numbers, the growth has been stolen from the working class and transferred via legislation put in place by bought politicians to the upper class.
Workers should have the right to a living wage, if an employer like Walmart doesn't want to pay that, they shouldn't be in business in America