This is not a comprehensible narrative. What the heck is a random aside about student protesters in the 1970s doing in the middle of—what? An advocacy piece about tax structure? Can you imagine if your boss asked you to put together a white paper on some issue to present to management, and you presented her something like this, with a few facts facts thrown in randomly between irrelevant filler anecdotes?
If you want to tell stories, then fine. If you want to write advocacy white papers making a factual argument, fine. But this is neither thing. It’s a hybrid form that uses narrative and anecdote to fill in for the extremely thin facts and analysis. What is the social value of this type of writing?
As to unions: what do they have to do with anything? Many countries with strong unions have see a similar or even greater decline in labor share of income. The US is not really much different than any other advanced economy on that front: https://www.mckinsey.com/~/media/mckinsey/featured%20insight.... In the US, labor’s share of income is less than France, about the same as Germany, and more than Spain. It’s significantly higher than Sweden, which has robust unions.
Moreover, nearly all the decline in labor’s share of income happened between 2000 and today. The decrease was very slight from 1947 to 2000. But unions stopped being a significant force in the US long before 2000.