[quuxplusone]

I'm not sure I follow the section titled "From periods to sentences." One of the topic sentences in that section is "Aristotle preferred periodic diction"; but I don't see any examples from Aristotle.

Instead we get an example from the Bible (Psalms 100:4), displaying characteristic parallelism but still with perfectly modern sentence structure: "Enter into his gates with thanksgiving, and into his courts with praise: be thankful unto him, and bless his name."

And then we get a new section heading, "Modern English emerges with bibles in the sixteenth and seventeenth centuries," quoting an identically constructed sentence from the same Bible (Acts 4:8–9): "Ye rulers of the people, and elders of Israel, [consider] the good deed done to the impotent man, by what means he is made whole," etc.

If there's any distinction to be made there, surely it's that the former quotation is from Hebrew and the latter from Greek — but then isn't it rather a little surprising that the exact same rhetorical device, this specific type of parallelism, should be used, than that there should be anything different about the structure of these two verses? But then — guess what — there's nothing different about their structure at all!

So what's the deal with that whole section (or pair of sections), and what actually is the author's thesis? What is the "great shift" mentioned in the headline?

If the thesis is that there was some big shift in sentence structure circa 1600, I'd say it's just demonstrably wrong. Look for example at Chaucer, circa 1400: https://chaucer.fas.harvard.edu/pages/tale-melibee-0 Nothing unusual about those sentences, is there?