The JW's have it all backwards. While they try and restrain their "materialism", they are acquisitive in other areas (reaching out, paradise). They start from a position of spiritual poverty. The Watchtower compounds the poverty by holding out the carrot of Paradise, creating a grasping, acquisitive, greedy people. That's why they are so miserly holding out forgiveness for others.
Succinctly put (adding to pile of "things I wish I had said") I can think of more jw's to whom this applies than jw's it doesn't. Still I suppose the mindset does tend to mirror the organisation's monetary bent.