Christianity is one of, if not the most counter intuitive faith in the world. God uses the foolish to shame the wise, the weaker things to defeat the strong, God can even use what man means for evil to achieve His good purposes. Should it surprise us, then, that those who are poor in this world also happen to be rich in faith?
Perhaps this is, as Francis Chan put it, "because they have mastered the one thing God wants above all else: Relying on Him for everything they have". Perhaps God's greatest gift may be poverty, because when you are no longer distracted by worldly things, you tend to seek the Lord to provide for you.
A stark contrast can be seen between the first and third worlds. The more we have, the more we want. As an apologist, I often laugh about the greed of many of the atheists I debate. While they complain that they're barely able to rent a flat, and so they can never believe in God, there are people in mud huts praising God for His mercies.
Although the context of James is a warning against personal favouritism shown towards the rich, I'd like to use it to encourage the poor. Fear not, you lack nothing, and the Lord has not forgotten you. Far from it; His power is displayed in you in ways rich people wouldn't even think about.