The “accomplishment the last 70 years” is NOT only a US thing, it is something that has affected most people around the world.
Since WWII Europe and many places in Asia has had to rebuild both their infrastructure and in many cases, their political system. USA escaped any damages to either.
The Marshall Plan helped both Europe and USA. Europe to rebuild and USA to keep their manufacturing base humming, until such time as there became markets to sell to.
China had the added calamities of the Mao-era and only really got started developing their economy 30 years or so ago. They have made remarkably well in lifting people out of poverty and developing their economy to where they are about to overtake USA as the largest single economy in the world.
You may not realize how much USA has gained from free trade and how much you have to loose by isolating yourself from it.
It is kind of stupid to spend 70 years preaching and pressuring other countries to adopt your policy of free trade and free markets, only to shut the door when you are ready to reach your goal and for everybody to reap the benefits.