Comment by pgeorgi

It's a bit more complicated: The US adopted[1] the international regimen (life + 70) with an exception that US statute of limitations from before 1978 continue to apply to works published in the US before 1978.

So the US adopted everybody else's rules but has an escape hatch for older works - that only applies in the US and this is where the contention over these 3-5 works comes from.

The US later extended the "70 years" rule for anonymous, pseudonymous and work-for-hire works to cover 95 years since publication or 120 years since creation (whatever happens first) because The Mouse squeaked[2].

I'd prefer Germany not to adopt that one.

[1] https://www.copyright.gov/help/faq/faq-duration.html

[2] https://de.wikipedia.org/wiki/Copyright_Term_Extension_Act