Oh we will, sooner or later...
matter cannot be created or destroyed, and only recycled. So we will never run out of water
Water is made up of 2 base components. When the base compo nets are released, there is no more water.
There's a lot that plays in to us running out of water. It will happen one day that there is no more water.
That is not what the NASA program is about. To live, plants, animals, and man need water. It makes up the majority of your body.
When we go to another planet to set up a habitat, we will need to have a ready source of water there. It is not feasible to carry tons and tons and tons of water with us.
THAT'S what the program and the crashing of the booster in to the moon is about. The plume can be observed through a spectrometer to see what elements are in it. If we find water vapor in the plume then we can take a closer robotic look from the surface. A robot can drill down and see if there are larger areas of frozen or liquid water. Then we park our asses in a rocket and zip up there.
Home sweet home.
Oh and that statement you're thinking of goes like this:
Energy can not be created or destroyed, only transformed.