What are you talking about? In what sense is history done by professional historians degrading in recent times? And what short/long term incentives are you talking about? They are the same as any social science.

"History done by professional historians" comprises an ever-shrinking fraction of the total available text.

Gen-pop is actually incentivized to distill and repeat the opinions of technical practitioners. Completing tasks in the short term depends on it! Not true of history! Or climate science, for that matter.