That graphic is done pretty dishonest.
First off... it's comparing 32 years with 27 Years... and that's important since they added together each growth number for each year. Actual growth per year being somethling like... 3%... at max.
Secondly
That trend didn't start in 1980.
It started in 1972.(or earlier) They use 1980 to avoid the fact that such a thing happened under Jimmy Carter, arguably are most liberal president ever.
A better graph would be this one. Though the data only goes to 2005... making it flawed since once the GFC hit, the top 1%'s wealth shrunk.
As you can see... the factor of difference is larger when you include the second Nixon term and Jimmy Carter, and exclude the GFC. Its actually a lot bigger.
Really though, it has nothing to do with policy, and everything to do with the kind of economic growth there was. The economic growth Post WW2 was an industrial boom created by unequaled amounts of "Free Trade" Policy created by WW2 and the need for it during WW2....
and the US being the number one producer in the word due to the US not having it's industries bombed into scrap.
Largely being a "Productions and Demand via free market" boom, it was more or less lower profit margin products that were around a while that required more workers. Hence the more even increase.
Versus now where largely we get "Growth by innovation". Some creates the next Ipad, and the next Ipad gets a HUGE markup being new and wanted.. So it has much higher profit margins. Since competition has yet to catch up with the new innovation.
