This is an argument of the 'wtf happend in 1971' thesis. I think however, there is another way of looking at it: by treating company profits and employee compensation as obeying a sort of conservation law. So if companies are hoarding profits that would go to workers, then this would be reflected in rising shareholder equity, so if employees invest their wages in stocks, the productivity-compensation gap is lessened. Indeed, the gap between productivity and wages began widening a lot in the early 80s, when the bull market began.