Way back in 20's or 30's, (someone correct me if I have the time frame wrong), the WT's strategy for witnessing was to give each publisher (or have them buy one) a phonograph to set on the householder's steps so they could play one of the Judge's speeches.
Flash forward and there was a testimony card that publishers handed to the householder, introducing them.
This gave way to the current model of the publisher being informed and able to discuss a subject with the householder.
That seems to be giving way to the new approach being used by the WT: the website.
The WT realizes that slick content is more impressive that a publisher talking, one who can't or won't keep up with the insane doctrinal changes.
Publishing books and magazines is taking the back seat; the WT and Awake have less than half the content they used to, and are published half as often.
The WT's trolley cart method involves not getting into discussions with people, but using an iPad to play them a video.
The past is the future!
The iPad and the website seem to be the new phonograph.