I would agree that the working class are or have been pivotal in the economic growth, but I think I would now argue that the old established and labour industries like mining, car manufacturing have been superseded by new technology and robots do many of these jobs previously carried out by the working classes. We have/are moving into the knowledge era and people with a higher level of education are in more demand. People like Trump and the extreme right wing are selling the working classes a line and promising them things which they can never deliver.
Globalization is moving on, nationalism is back to future