You are correct that the original US copyright law was set to the reasonable maximum of 14+14 years, however that was extended to 28+28 years already in 1909, not exactly a relatively recent development.

In 1976, 35 years ago, it was further extended to 75 years after publication or 50 years after death of author. In 1998 it was extended further to an insane 120 years after creation or life + 70 years.

Even if the copyright length insanity actually only was a relatively recent phenomenon from 1998, I don't see why that would exclude it from the "outdated" term.