It was never going to be possible for the US to maintain that kind of standard of living forever. It worked out in the 1950s through to the 1970s because WWII left huge swaths of industry and agriculture in Europe and Asia devastated — it took decades^0 for affected countries to rebuild. Meanwhile, North American based manufacturing soared and became the envy of the world — everyone bought form North America, and anyone with no particular skill set who was looking for a job could get a good Union job in any number of factories.
But that couldn’t last forever. There was no policy the US Government could have taken (other than perpetual war against everyone else?) that would have kept the rest of the world from re-industrializing. Japan, China, Germany, Italy, France, and the UK (amongst others^1) were able to re-industrialize to a point where the US suddenly had competition again — and while the US could have some competitive advantage against some of its more Western allies due to size, they weren’t going to be able to keep that kind of lead forever against China, Taiwan, and Japan. The world wound up with more capacity than there was a market for, and so the winners were the ones that could do the job the cheapest (as is the way in a competitive marketplace).
It was an anomaly that brought the kind of prosperity the US experienced in the post-WWII years; you can’t recreate that today (as it’s only due to the limitations of the technologies at the time that North America was broadly spared any destruction during the war years — in the post WWII nuclear/ballistic missile era that wouldn’t be the case anymore).
^0 — there are still areas in Europe that are uninhabitable (and unfarmable) today due to WWI and WWII.
^1 — it did somewhat help that the Soviet Union re-industrialized under Communism; the generally closed nature of their economy, combined with the huge inefficiencies of most of its industries under centralized control didn’t really challenge or threaten the US’s economic might.