Although there’s reason to fear for the long-term future of historical studies in the US in general, one shorter-term cause for alarm is the chronological flattening of departments to concentrate overwhelmingly on the period after 1900. There are several reasons for this.

Many history departments are under tremendous pressure to shrink by not replacing faculty who retire. Since new hires have to pass through approval by deans, potential enrollment is a major criterion.

Some have false sense that recent history draws best. Courses in the history of the Mediterranean ancient world, early China, medieval Europe, the samurai, etc., can be extremely popular, sometimes among the largest courses in certain departments. Students don’t want just 20th C.

A distinctive feature of history as a discipline is that training requires specialization for languages, sources, and context. Social sciences may emphasize universal methodologies, but historian of Japanese history would require years of retraining to shift to China or Russia.

So in a history department it’s hard to genuinely do more with less. Even excellent trans-regionalists will have difficulty getting fully-trained and competent in more than two regions, especially if two languages are involved. So when faculty shrinks, things just get dropped.

Departments committed to global coverage that can only hire one historian of China, Japan, Russia, or Brazil, will almost certainly favor 20th C as more relevant and likely to draw students. Only the largest departments will be able to hire multiple historians in these regions.

20th C historians will also find it easier to persuade future colleagues, likely to be majority Americanist in the US, that 20th C Egypt or Japan or South Africa speaks to their existing interests and concerns. A pre-20th C historian would face more complex task.

I think there are two potential vicious cycles here: As history departments get more 20th C heavy, there will be fewer early-period specialists to speak up for the relevance and importance of pre-20th C history when future hiring plans are debated.

The second is training: Ancient, medieval, or early modern history requires talented students to commit to arduous technical training in the face of a pretty dire job market. Beyond a certain point, if there are no jobs people just won’t go into certain fields and they’ll die.

20th C history is extremely important, but I don’t think it is alarmist to suggest that in 30 to 50 years such US history departments as still exist will be overwhelmingly concerned with events after 1945, particularly for the world outside the US.

A fundamental intellectual premise of historical study is that more recent events are not necessarily more relevant for understanding the world, rather, such understanding requires a balance between long-termer and more recent developments.

One of the most seductive wrong ideas in history that there are recent “modern” developments that "changed everything" and made earlier periods of merely antiquarian interests. If pre-20th C history fades out, there will be fewer voices to argue against this idea.