We saw a slowing of per capita growth and an increase in income and wealth inequality starting in the early 1970's.
I present a few things that might be driving this trend.
One accelerating inflation
The 1970 was the end of a long period of accelerating inflation. Accelerating or unexpected inflation tends to help what I call commodity labor (that is worker that do jobs that almost anyone can do with a few hours of training).
This is because it fools businesses to thinking there is more demand for their products than there is and so to hire more employees.
Part 2 NIMBY
Some have contended that the reduction of Government action in the 1970's slowed economic growth and increased income inequality and lower quality of life for bottom 30% of earners. but it appears to that NIMBYism and a reduction in law enforcement are primarily to blame.
Here's an anonymous quote on the subject:
"Seeing the price of TVs falling down and down- and understanding that was capitalism." "Seeing the price of a flat in London going up and up and up- but being told this was also capitalism"
NIMBY has made it more expensive to build anything. Bryan Caplan says the top economist studying the rise in housing costs estimate that the typical US home is 2x as expensive due to NIMBY. NIMBY, though mostly a left generated movement is even slowing the expansion of green power.
Letting NIMBY's block owners from building is transferring some ownership to voters. In the 1970's people started to gain power to stop even residential building.
Here is Matt Rognelie of Massachusetts Institute of Technology answering the question of what is driving the growth in inequality he lands on NIMBY.
Not only does NIMBY make housing more expensive but also construction is large employer of men without college degrees and has historically paid more than the manufacturing jobs.
It also increases inequality by keeping low earners from moving to places where pay is higher.
3 Crime
There was a rapid increase in measured crime and disorder in the mid 1960s. It might be measurement error (some contend that murders with Black victims were under reported prior to 1965), but it might be partly due to the Democratic, in attempt to reduce police and prison brutality went more with reduced sentences and getting criminals off, to punish the system rather than focusing all their efforts on reforming police and prisons. leading to more crime in poor areas degrading life and increasing divides that would impact inequality in standard of living. BTW it might even be that more police would lead to less abuse rather than more.