Note the date—1974 in both websites--
“More than 40 years ago, a small group of state legislators and policy advocates met in Chicago to implement a vision:
A nonpartisan membership association for state lawmakers who shared a common belief in limited government, free markets, federalism, and individual liberty. Their vision and initiative resulted in the creation of a voluntary membership association for people who believed that government closest to the people was fundamentally more effective, more just, and a better guarantor of freedom than the distant, bloated federal government in Washington, D.C….”
Source for above.
See what happened to incomes--.01% vs 90% after the start of this group in 1974 on this graph.