I'm a 4th gen born in, but I think many become JW's since they are in a very difficult time in their lives.
They pray and pray and pray, and then someone knocks on the door.
It may be a JW at the door ... a person from the post office delivering a package ... someone offering to put a new roof on their house ... whatever.
That's just how it is rationalized that God sent the person in the darkest time of need.
In a few weeks, the person will be at the KH, delivering packages, or putting new shingles on someone's roof.