What you said is all well and good, but i fail to see its relevance. Yes we might be able to be succesful in our tasks through use of science, but we cant 'explain the universe' if we cant even be sure it is there. Just because we all seem to make the same observations isnt justification for assuming they are an accurate representation of reality. We dont even know if other people really exist, we just assume.
This is what we mean by metaphysics, things as they are in themselves. We cant ever really know, or even know if there are 'things'.