You forget 4) duty. that is probably the single biggest one -- sometimes components have a lower tariff rate than assembled final goods, and sometimes it makes sense to import low-value products and do a magic high-value "assembly" step in the country or compact (EU, NAFTA) of sale, if taxes are lower than duty, or if you can make the "assembly" step involve "purchasing and installing software or a license", and thus an expense, but not a tariff-subject item.

The ultimate examples being "pressing boxed software". Assemble the box, manuals, etc. in a certain country, add the value during that step in the form of components, with the license not being dutiable, but a boxed software item imported would be.

Regulatory arbitrage at its finest. This is pretty much why Apple makes some iPads in Brazil now.

The article did point out that the requirements for declaring something to be "Assembled in USA" are a lot more stringent.

The US also has low duties; it's mainly about some other countries, usually in the developing world, which have higher duties and more broken enforcement regimes.

Also the US has weird loopholes with some territories or other treaty countries, so you can do less work to make something "made in USA" in some places and some industries than in others (I think Saipan, American Samoa, Puerto Rico have special status)