Colonizing != visiting. There're many possible economic benefits of colonizing the moon - new sources for rare minerals, reduced population pressure on earth, and a launch pad for future interplanetary missions are some of the major ones.
And getting all those minerals back to Earth, and building sustainable communities on the moon, costs as much or more than the value derived, hence zero ROI. And we're not going anywhere in space till we have more efficient propulsion than we have now. Isn't the energy/propulsion problem the one we should be focusing on first?
Why would you bring those minerals back to earth? You mine minerals on the moon so you can manufacture things on the moon, so that you can build the machinery necessary to visit other stars outside of earth's gravity well, so that you can reduce the energy needed to launch an interplanetary expedition, so that you can solve your energy/propulsion problems.
