I think I know why Jesus said that the poor will always be among you (or at least one of the reasons)...
As christ followers, we are to be generous with our brothers and sister in Christ who are in need.
And we are selfish people. Period.
If we kept only what we needed to live on in the US, and gave the rest away to those who really needed it, the body of Christ would be taken care of.
So maybe the poor would still be among us, but maybe those who know the Lord would not be fighting each day to survive.