A lot of it is politicians chasing a golden age where everything lined up for American prosperity which we can't really return to. The postwar period had so many things going for America, everyone else was rebuilding or bankrupt, immigration was very low, the majority of global capital was USD, strong capital controls meant domestic investment which hindered outsourcing and de-industrialization and the monetary policy of the time was reacting to prewar era of massive unemployment that led to political instability in the world, so they focused heavily on full employment to maintain stability.

Focusing on full employment meant wage growth was persistent since it was always in high demand, which worked because it was paid for by the gains in innovation from those workers, and the rest of the world was catching up and created demand creating a cycle. The cycle eventually became unsustainable because at some point innovation gains could not keep up with inflation and the world became more competitive as everyone caught up. Labor had a lot of power in this regime but if it was not worth it for capital to invest since there was no return, they would stop investing because the scales of power tipped too far in the favor of labor, which led to unemployment and stagflation.

The response to this was to shift monetary policy towards taming inflation and creating price stability. The pendulum swung hard in the other direction against labor. Interest rates were jacked up and the financial system was liberalized to entice lending, women are entering the workforce and immigration is taking off and capital (and labor) was going international to where it got the greatest return. Inflation was crushed, the power of domestic labor was gutted but interest rates were still high, which led to the financialization of the economy because lending became so incredibly profitable. Everyone wanted money because they were previously credit starved, and everyone wanted to lend money because it was so profitable. Since price stability and taming inflation were the goals of policy and liberalized credit gave the gains that traditionally went to the working class to the developing world, wage stagnation was inevitable, which put a hard limit on growth unless growth was to be increasingly fueled by more debt. Inequality shifted dramatically because gains on capital were very high and gains in labor were very limited, and limited to those who interacted with the financialization of the economy (finance that ran the system, technology that innovated the system and the other industries that worked in tandem like big law).

This led to 2008 when everything was so levered that things started to fall apart, but instead of letting it fall apart, governments wanted to keep the sinking ship alive, and so central banks stepped in to provide the liquidity to keep things afloat. Keeping things afloat exacerbated the problems that the system perpetuated, only now it is being pushed to the extreme because the only way forward is even more debt which creates even more inequality which is where we are now where we have crushed interest rates to keep the party going and can barely raise them without blowing up the economy, and the rise of working class populist movements across the developed world.

This is basically a summary of a lecture given by Mark Blyth on the subject which can be seen here: https://www.youtube.com/watch?v=tJoe_daP0DE