Your sense of history sucks especially about the early 20th century. Ted Roosevelt used the Sherman Act to bust up RR, steel, banking, and oil trusts amongst others. He helped usher in consumer advocacate ins utions like the FDA. You had a period of largesse following ww1 but then there was the crash and special interests lost their hold. That is why things like the income, capital gains and corporate tax rates were where they were at.
Prior to that era everything was dominated by industrial elites in the north and prior to 1864 plantation owners in the south. Look up the gilded age. The downward trend began in the 1950s and the cold war and most recently with the NDAA and establishment of the HSA.