It might not be economical to ship it back to Earth. But launching from the Moon is far cheaper than launching from Earth, so if there is ever a significant demand for materials in Earth orbit it makes sense to supply from the Moon.
This is so far off, though. Whatever raw materials you mine from the Moon need to be refined and then you probably need to manufacture something from them, with any other components of the manufactured product being imported from Earth. Not saying there would never be a plausible scenario, but it's so far off, with nothing even resembling a hypothetical plan at this stage.
