other cruches around shorter time than JWs have accumulated more members without door to door
JWs numbers would literally double over night if they stopped door to door... many holding back because of fears of door to door work.
so why continue?
in the book THE TRUE BELIEVER it says something along the lines of Nazi Goose stepping... the reason is nothing more than a control issue. the more you can keep people doing meaningless and useless activities, the more you have them under your control.
JWs say Hypnotism is binding with a spell and condemned in the bible, yet everything they do is a form of hypnosis, which in its basic form is just allowing someone else to do your thinking for you.