Peter Temin describes the rise and fall of economic history at MIT in the History of Political Economy and an un-gated version here. Temin also talks about the costs of not having actual economic historians, even if you do have people who write about history.
MIT isn’t the only place to experience a rise and fall of economic history. My grad school (for my econ Ph. D.) has pretty much completely turned its back on economic history. When I was there we had Douglass North, John Nye, and, for the last year or so, Sukoo Kim. There was a well-attended history lunch every week. Doug retired. John went to George Mason. Soks is still there, but my understanding is that he is not very involved in the economics department. History is not listed as a field for graduate students. The economists that replaced the economic historians have demonstrated the potential problems associated with model makers using the past without consideration for the historians concerns with context and source criticism. Boldrin and Levine use the example of James Watt to argue against patents. On the actual influence of Watt’s patent see Selgin and Turner “Strong Steam, Weak Patents” JLE 2011 or Bottomley’s British Patent system During the Industrial Revolution.
My wife’s grad school also moved away from economic history. While she was doing her graduate work at Illinois they had Jeremy Atack, Larry Neal, Lee Alston, and Charles Calomiris. Now, if they have an economic historian, I don’t know who it is.
Fortunately, it is also possible to name departments where economic history is either on the rise or holding its position, with multiple economic historians and consistent production of good Ph. D. students. UC Davis, Yale, Vanderbilt, George Mason, and Northwestern are some of the schools that come to mind. My apologies to the other good schools I did not mention.