The 80 started caving in to the 20, I am convinced, when the 20 got serious about putting a plan together to impose their will on the 80.
By planning, working their plan, refining their plan in a planned twice yearly+ cycle of meeting, planing, executing their plan they proved successful...
They won because the 80 run in circles, scream and shout, and refuse to agree to come together in cohesive unified strength.
The 80 is also hampered by work ethic and moral/religious strongholds (they mostly hold down jobs, maintain households, and try to enjoy the fruits of their labors)
The 20 is limited only by their intellect and need to rely only on "reason" = the voices of their imaginations, and a need to control other people.
So the 20 took over the educational system which molds = forms = world views & paradigms, and all "approved knowledge".
the 20 put people in places of influence: school boards, town councils, local governments and agencies, state legislatures, national congresses
and of course labor unions...
100 years of persistent influence from grammar school through high school & colleges...well...
yielded what we have today.