Jesus, and later Paul, did not knock on doors! If Jesus knocked on doors and tents, his short ministry would have accomplished nothing. They went where crowds of people would be - markets. Within this past month, I read Ehrman and Crossan both describe Paul's strategy. He set up a small business that would drawn his target crowd. During normal business conversation small talk, he would start mentioning Jesus. People would have run if he preached forcefully at them. Talking with someone is very different than talking at them.
Within the past day, a similar thread was active. I don't understand why the Witnesses don't use mass communication. People despise the intrusion of privacy that knocking on doors entails. In the beginning, many businesses knocked on doors. Businesses no longer just knock on doors. Technology offers so many ways, unimaginable in my youth, to target and reach people. I don't see what the WT does with its assets. Bethel may be nice for the leaders but they don't live the way Donald Trump or Michael Bloomberg do. Another poster said knocking on doors keeps people occupied. It allows control over individuals that would not be present with tV or radio. When my mom was young, the Witnesses had a successful radio station. The main DJ became more popular than Rutherford or Knorr. Witnesses loved the station. End of station.