Here is how the Bible describes some people who were faithful to God:
That certainly doesn't sound as if serving God made them prosperous.They were stoned, they were sawn in two, they were killed with the sword. They went about in skins of sheep and goats, destitute, afflicted, mistreated—of whom the world was not worthy—wandering about in deserts and mountains, and in dens and caves of the earth.
(Hebrews 11:37-38 ESV)
In addition to this I am sure most of us have known people who lived Godly lives but never had much money.
But in spite of this apparent evidence the basic premise of the prosperity gospel is true. God does want all of his children to be rich and he will make us rich if we obey him. Their error is that they define wealth in terms of material wealth. Here is the true prosperity gospel as Jesus described it.
Fear not, little flock, for it is your Father's good pleasure to give you the kingdom. Sell your possessions, and give to the needy. Provide yourselves with moneybags that do not grow old, with a treasure in the heavens that does not fail, where no thief approaches and no moth destroys. For where your treasure is, there will your heart be also.
(Luke 12:32-34 ESV)