*jumps into this discussion*
Sometimes God decides to use people to answer prayers, so if someone goes and gives a starving child some food, their prayer is being answered and God is being glorified. Jesus told us to do this. He gave us the opportunity to serve Him by doing what is in our power to do, and pray for what we can not do.
Actually, I have friends who are not 'middle class white Americans with above-average medical care', and their family members were cured by prayer. There are poor people who were healed as well.
What evidence are you basing this on?