Unregenerate humans are self-interested. Capitalism attempts to channel this aspect of human nature most productively by offering compelling incentives for action.
Christians can overcome self-interest by responding to the call of Christ and obeying His commands.
The response to Christ does not guarantee positive social or personal outcomes! Rather, we are promised persecution and trials, in short the cross of Christ, for our decision.
The enemy of both systems is power, or the use of force. The use of force removes the restraint on self-interest which permits individuals from realizing mutual gains from exchange. The use of force likewise corrupts the message of the cross.
Christians ought to work first to eliminate force from their own habits. Second they should work to protect the victims of the use of force. Third they ought to work to restrain the use of force.
Only Christians are capable of acting out of conscious virtue in imitation of Christ in the renunciation of, protection from, and resistance of force unselfishly. In other words, most people can take care of themselves fine so long as they allowed to defend themselves and care for themselves out of self interest. But for the defenseless and incapable God has provided the Church as a means for overcoming this world.
Capitalism works up to a point, but it neglects the least of these. It does tend to raise the welfare of all participants albeit disproportionately. Christianity has as its unique mandate to care for those who are stuck outside of the Capitalist system.