This was exploited from the other side by sending billions of low-value packages, so now the EU adds €3 per article category (so 2 shirts = €3, 1 shirt and 1 spoon = €6) to every package that's under other customs thresholds (€150 usually). With the view this will be eventually replaced by automating the tariff calculation for every package in a few years.

As a result, the number of imported packages dropped anywhere from 30% to 80%, we'll have to wait for the full numbers, but there is a reason to expect something similar will happen in the US.