I think they want to get people in asap before they have a chance to ask too many questions or do research, which is so easy to do these days.
In the old days, we took people through the Truth book, if they weren't coming to meetings within 6 months or by the end of the book, we dropped them. People were coming in so fast and I remember the brothers saying they were coming in too fast and not shedding their world habits which was creating a lot of problems for the elders!
In the congregation I have now left, there is a sister there who studied for 15 years before she took it seriously and got baptised. My dad studied with people for years, as well. They often came in - eventually. My dad said we can't hurry people...this is a big decision. He got that right!
End of the day, they want them in because they need the money and perhaps they are worried about the effect apostates are now having.