Enjoying King's breezy exploration of his writing - its genesis, its voice. I hungered to read it, if anything to understand Mr. King's volumetric prowess (happy 69th, btw). Wikipedia has him at 54 fiction novels, 6 non-fiction, and 200 short stories. Unfortunately, half-way through and I'm no better off knowing his magic tricks for velocity. (He lists his habit of writing, which must include fingers that simply don't stop.) But, yes, where I paused is taking a hard look at passive versus active voice.
From the NY Times, "The Pleasures and Perils of the Passive", by Constance Hale:
"The most pilloried use of the passive voice might be that famous expression of presidents and press secretaries, “mistakes were made.” From Ronald Ziegler, President Richard M. Nixon’s press aide, through Presidents Ronald Reagan and Bill Clinton — not to mention Attorney General Alberto Gonzales — pols have used the passive voice to spin the news, avoid responsibility or hide the truth. One political guru even dubbed this usage “the past exonerative."
From The Elements of Style, which King alludes to often:
"The habitual use of the active voice, however, makes for forcible writing. This is true not only in narrative concerned principally with action but in writing of any kind. Many a tame sentence of description or exposition can be made lively and emphatic by sustituting a transitive in the active voice for some such perfuntory expression as there is or could be heard." - page 18
So where did this change occur? With the drive for simplistic concepts and a packaged coalescence (Apple I'm looking at you), there is data to support that modern English and grammatical complexity has forced us into an active narrative. Passive, grammatically complex structures make those with less education primarily guess for meaning. When I read Henry James or Thomas Mann, there was a 'flowery' style that may be less active than say a Mark Twain or a King.
Examples are illustrative and abound at yourdictionary.com:
PASSIVE:
'At dinner, six shrimp were eaten by Harry.'
'A scathing review was written by the critic.'
COUNTER/ACTIVE:
'Harry ate six shrimp at dinner.'
'The critic wrote a scathing review.'
It's easy to see that, in passive, the receiver of action comes before the doer (receiver-action-doer). It naturally requires the reader to think out of order of doer-action-receiver.
Much to think about as you analyze your own writing. Interestingly, Grammar Girl recommends that science fiction should always be in passive. Circling around to me spinning in circles, trying to keep the moon in sight and screaming "no one really knows!" But, there is a ray of light, in that last chapter of Elements, "'What if I am a pioneer, or even a genius?' Answer: then be one."