Evangelicals, Mormons, Muslims, etc. are much faster growing. Growth numbers or rate is not proof for or against being true religion (nor is door knocking!).
I hope to live to see the day where WT shrinks more and more like other pseudo-Christian cults have.
In fairness, it is also a sign of the times that so few have any interest in God, church, etc. One would think with the massive hours put in, JWs would have more success. A small group with the Holy Spirit can have more impact in a month than a large group without the Holy Spirit (active force insult to Him) can have in years (Christian revivals are exciting and change whole towns/cities/lives, not just one or two people talked into something).