There really was a vast right-wing conspiracy. It started with this memo.[1]
Here's the background: [2]
Understand that, before this, businesses rarely had lobbyists or engaged in political action. That totally changed in the 1970s.
[1] https://www.greenpeace.org/usa/wp-content/uploads/2021/08/Po...
[2] https://billmoyers.com/content/the-powell-memo-a-call-to-arm...