Phizzy:
Door to door sales were the primary way of selling products in the 19th and up to mid 20th century, The Watchtower is only 75 years outdated in its methods.
Vacuum cleaners, encyclopedias, Homeopathic medicine, soap, brushes, make up and Watchtower and Awake magazines were all sold by travelling salesman. In the 1950’s cars became more reliable and roads became better so people could travel to central locations to pick up what they needed. In addition to this the 1970’s saw an increase of women in the workforce so there weren’t as many people at home during the day and the door to door sales method died out. The final nail in the coffin was the internet. You can get whatever you need delivered right to your door with the click of a mouse.
The watchtower organization are extremely late to the game.
You are right though about the busy work. If you keep members so busy they don’t have time to think, they probably won’t leave the organization