It is unfortunately a problem with academia itself. In order to get PhD in history, one needs to be able to conduct new and novel research. The big important things have been covered, usually by experienced and skilled historians, so the newbs find themselves drawn to less studied topics. Social histories provide the perfect ground of this. This is further influenced by a serious problem facing modern historians; too many sources. It is quite possible for a single historian to be an expert on, say, the Roman Empire. But the Modern British Empire? Nope, there is just too much information for a single person to master it all. This is only getting worse with the internet; to be an expert of the Iraq conflict, for example, could take an entire lifetime! Thus, people specialize into limited areas and the field is not set up for significant collaborations, thus these specializations never get connected with the larger historical narrative (narrativistic history generally being pooh-poohed since post-modernism). Historians need to be set up a little bit more like research labs, where four, five, or more historians of different levels are all working together to actually form a full, coherent account.
If that wasn't enough, Academia in general is structured to produce clones, not unique investigators. Would-be historians are supposed to find a mentor and make themselves a clone of that individual, so they become limited to a specific specialty field long before they are even fully trained; they can't usually make the switch to another field, so their career then focuses on just becoming more specialized and more distant from humanity itself. Thus we get specialties of specialties of specialties, such as the development of eating utensils in the Caucus mountains (oh how I wish that was a joke)!
... I don't have personal issues with the academic complex in the field of History, honest!
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Okay, maybe a little.