This book is even more vile than you say, and it shows how twisted some religious folk can be. I've read the book in quiestion and found it very poorly supported. The author built a whole theology around a minute passage and as you so aptly pointed out drew a direct correlation between God's favor and personal wealth. Thus, the stratification of the classes is now a sanctified tradition. Western Evangelicals no longer have a compulsion to aid those in need because those in need don't have material possessions because they aren't asking God for enough. This is reminiscent of early Calvinism. Anyway, then came the mugs with Jabez' prayer, the bumper stickers, the version for women for children for teens, the illustrated version, the leatherbound version, the Prayer of Jabez journal. And this excess is justified by the message the excess brings. Bruce Wilkinson, the book's author, is enjoying financial gain because he had the guts to ask God every day. I fear that such theologies as is represented in the "Prayer of Jabez" are created in order assuage the guilty conscience of those who live in plenty, who attend the mega churches, who live in the suburbs, who want more, and don't want to have to share.
Well Jesus had another message, "Go sell everything you have and give to the poor. It is easier for a camel to go through the eye of a needle than for a rich man to enter the kingdom of God."
These people need to get a clue.
Benjamin Gramlich