It seams to me that these prosperity preachers have overlooked what the bible has to say about riches, probably because they are blinded by their own greed.
Proverbs 30:8 says: "Give me neither poverty nor riches; Feed me with the food that is my portion, That I not be full and deny You and say, "Who is the LORD?" Or that I not be in want and steal, And profane the name of my God." The writer of this proverb is basically asking God to supply him with his daily needs, neither poverty or riches. Just as Jesus instructed in the lords prayer, "Give us this day our daily bread." Matthew 6:11. It is also interesting to note why the writer of this proverb, said this. Because he did not want riches to cause him to loose his trust in God.
The Apostle Paul said the exact same thing in 1 Timothy 6:7-10, "For we have brought nothing into the world, so we cannot take anything out of it either. If we have food and covering, with these we shall be content. But those who want to get rich fall into temptation and a snare and many foolish and harmful desires which plunge men into ruin and destruction. For the love of money is a root of all sorts of evil, and some by longing for it have wandered away from the faith and pierced themselves with many griefs."
It seams to me, God has promised to provide us are "daily needs," not our wants of fabulous wealth. In fact Paul wrote in Hebrews 13:5, "Make sure that your character is free from the love of money, being content with what you have; for He Himself has said, "I WILL NEVER DESERT YOU, NOR WILL I EVER FORSAKE YOU."