I don't have a strong opinion on the subject, but I believe/hope it should be possible to be accessible and entertaining while still being academically "acceptable" in terms of references (which doesn't need to be of the form 1 claim, 1 reference) and without taking misleading shortcuts or trying to sell your new universal theory of history, but sticking to consensual understandings and/or prefacing your novel ideas adequately.

I guess it sells better if you can make your audience believe that your theory explains "everything". Having read the book, it's a better feeling to think that you now understand the gears of history through this new lens, rather than it being just a complex jumble of interconnected stories/phenomena.