To answer your first question, consumers care about manufacturing costs every time they agree to pay the producer of a good the producer's asking price. But, this is not so much about caring about manufacturing costs as it is about respecting ownership rights.
In any case, it's really splitting hairs to say that it's copyright infringement vs. stealing. In fact, I believe that making that distinction is what is disingenuous. To the extent that a copyright has value, it's because people respect that it represents ownership of a thing and, thus, the right to capture any value that the thing produces. When we don't respect that, then we have effectively taken any value from the creator for his/her creation. Meanwhile, we enjoy value from the creation, whether we use it for ourselves, re-sell it, or otherwise. How is that not stealing?
I do get that people have always made a distinction between copyright infringement and stealing, but my question is why is that so? Actually, my original question extends further than that to ask, why is it that people additionally feel entitled to do so?