I suspect in many cases, the "value add" an American firm provides is an intangible.
In the pre-tariff omnishambles world, I could buy a more or less equivalent widget for $18 branded with a recognizable American brand, for $12 as a KWJIBO non-brand delivered from Amazon, or for $6 more-or-less manufacturer direct from AliExpress.
Amazon added $6 of value by saying "I can get it to you in a timely manner and offer a confidence-reinforcing return policy."
The American brand added another $6 of value for "this can probably be sourced consistently and people won't look at you weird trying to get it Shenzhen Tchang Zu Shrimp Cannery And Electrolytic Capacitor Plant #5 onto the approved vendor list."
They didn't actually improve the widget itself, just logistics around it. That means their value-add is extremely tenuous, and has a limited moat.
In the pre-tariff omnishambles world, I could buy a more or less equivalent widget for $18 branded with a recognizable American brand, for $12 as a KWJIBO non-brand delivered from Amazon, or for $6 more-or-less manufacturer direct from AliExpress.
Amazon added $6 of value by saying "I can get it to you in a timely manner and offer a confidence-reinforcing return policy."
The American brand added another $6 of value for "this can probably be sourced consistently and people won't look at you weird trying to get it Shenzhen Tchang Zu Shrimp Cannery And Electrolytic Capacitor Plant #5 onto the approved vendor list."
They didn't actually improve the widget itself, just logistics around it. That means their value-add is extremely tenuous, and has a limited moat.