There are a lot of factors involved. Deregulation - free market allowing outsourcing of manufacturing and stripping labor of unions/workers rights reduced power. In the 70's the green revolution was starting to make headway. Most of the EPA laws and movement towards cleaner energy derived from this era, but were squashed when environmental laws were reduced/eliminated and companies could move overseas to countries with less restrictions.

Government policy always needs to change to keep up with trends, but at this point it's safe to say funding businesses instead of people has resulted in monopolies. There are less jobs and wealth for income earners, and government has reduced spending in public goods. The government could create jobs by creating much needed public services (better education providers, healthcare, environmental technologies, etc), but it hasn't done any of these things in decades.