[tomder55]

The reason is we don't need them.

After WWII nobody was making stuff but us. It was inevitable that as nations recovered they would begin making stuff too if for no other reason than to sell to their own people. . We encouraged it . The Marshall Plan had dual purposes ....to defend Europe from a Communist takeover ;and to create markets for our industry

Although it appears we have lost market share as people like Ross Perot and Peter Navarro claim . The truth is that as a share of GDP ; manufacturing has not lost much since the 1940s . According to the St Louis Fed ;Manufacturing's share of real GDP has been fairly constant since the 1940s, ranging from 11.3 percent to 13.6 percent. It sat at 11.7 percent in 2015.
Is U.S. Manufacturing Really Declining?

What has declined is factory employment . And that was as inevitable as farm employment declines.
Statistics: Trends in American Farming | Gilder Lehrman Institute of American History

Efficiency in production means you need less people to do the same job.

This not just true here . It is true world wide

Manufacturing accounts for a relatively small and declining share of total employment in rich countries - Our World in Data

Hate to break it to Trump (even though I'm sure Musk must have laid it out for him by now) Robotics and AI are going to accelerate the decline in factory employment.

The biggest challenge facing American leaders today is what kind of jobs will be need in the future ;and how do we prepare the future work force to meet the requirements of those jobs ?

[jlisenbe]

The biggest challenge facing American leaders today is what kind of jobs will be need in the future ;and how do we prepare the future work force to meet the requirements of those jobs ?

Good observation. Number one job for men in America is truck driving. The time is not far away when robotics will take over at least the interstate portion of that driving. It all concerns me.