JWFacts you hit the nail on the head: JW's show a great lack of faith. Others may have said it in the past but you're the first one to make the comment that I've read. The JW's like to take it upon themselves to try to make things happen or take credit for things happening.
Clarity ... A scripture that comes to mind is Acts 17:11,12:
11 Now the latter were more noble-minded than those in Thes·sa·lo·ni´ca, for they received the word with the greatest eagerness of mind, carefully examining the Scriptures daily as to whether these things were so. 12 Therefore many of them became believers, and so did not a few of the reputable Greek women and of the men.
A quote from an article published by the WTBTS:
How can we do God’s will? We have to learn what is “fine and acceptable in the sight of our Savior, God,” and then choose to act accordingly. (1 Timothy 2:3) That involves taking in accurate knowledge of God’s Word, the Bible. (John 17:3; 2 Timothy 3:16, 17) More than just casual Bible reading is involved. We need to imitate the first-century Jews in Beroea who heard Paul’s preaching. Of them, we read: “They received the word with the greatest eagerness of mind, carefully examining the Scriptures daily as to whether these things were so.”—Acts 17:11.
The simple answer to the JW you're addressing is this: Christians in the first century ( as cited above in Scripture and acknowledged by the WTBTS) examined only the "scriptures" daily. They didn't have the WTBTS, they didn't examine the "Scriptures and the Watchtower with printed questions at the bottom of the page for each paragraph. The scriptures were sufficient.
Not just a few became believers via this method - many. And that's how "anyone could learn the truth with only a Bible".
Shocking huh?