Here's a test to see whether "period style" makes the difference between good, bad writing etc: (yes, I do know that these weren't "histories" in the terms we have been discussing): Compare a page of the very similar (in intention, subject) memoirs written by each of the exact contemporaries: Gleig, Aitchison, Harris, Schaumann. Compare each of these with a page of Wellington's/Moore's letters. You will readily see (as I'm sure you already know) that style varies enormously among them. There is such a thing as period style, but some of these writers are so dull that you struggle along with difficulty, some vague, prolix, florid, while others are to the point, clear, straightforward, even racy.
I don't believe that in any real terms a gap has opened up between academics and populists. While there is such a gap, it appears greater today because both fieldshave expanded considerably recently. It's not an impassable divide. Some of the best popular books are written by academics - so to pursue the argument, a few terms would have to be defined. Again, as argued elsewhere on the forum, it's more often a question of horses for courses.
One thing puzzles me about the posts - the reluctance to give the laurels to today's writers? I stand by my belief that history writing is better today than it ever was.
A wild card: the book in my own field that I would most like to have written: Leo Steinberg's "The Sexuality of Christ in Renaissance Art and Modern Oblivion." (catchy title, eh?) The book deals with a topic virtually untouched previously but of considerable interest, and deals with it with a wealth of detailed scholarship lightly worn and immaculately deployed; written stylishly and elegantly, with flair; clear, beautifully structured and with meta-historical and meta-iconographic questions well considered and well integrated into the overall structure. Even more of an achievement considering what a difficult, touchy subject it could be if ineptly handled.
Something to think about - the book everyone would like to have written?