Aluminum and steel tarrif's went into affect in 2018 and stayed in place. Here are some current projects I know about:Automation works just as well overseas.
In the US, our environmental laws, declining workforce, along with the extreme expense of construction get in the way.
CEO's believe these policies are temporary & are unwilling to spend big (on new US factories) in the event the tariffs stick around more than 4 years.
Steel Dynamics is building a brand new aluminum mill in Mississippi. Opens this year
Novelis is building a brand new aluminum mill in Alabama. Opens next year.
Arcelor is just finishing a electric furnace in Alabama - I believe its operating or close. They used to ship slabs in from off-shore.
Steel dynamics opened a brand new rolling mill in Texas in 2023
Nucor built a new mill in Florida - opened 2020
Nucor just announced a new mill to be built in WV and Hyundai just said there building a new mill in Louisiana.
These are just the ones I know about. There are lots more outside my neck of the woods.
I believe your assumption is wrong