I agree that, specifically, music and movie estimates are ridiculously overstated. However, we have no means of measuring the total, fundamental economic losses due to a culture which no longer values intangible things.
Assuming you're a software engineer, do you want to proceed into a world where people shell out thousands of dollars for an iPhone, but scoff at paying $1 for software you've worked hard on? Current (and presumably future) attitudes toward (intangible) IP are dangerous to the economy we're developing.
Comparison infringement to things that kill people don't help you, even if that wasn't the main point.
Okay, substitute something non-lethal. People send their kids to school even when the kids are sick. This is bad for everyone. Do we just accept it, or do we remind people to keep their kids at home when they're sick? If you want more analogies, I'm sure I can come up with them, but I would prefer to simply have the question answered with regards to giving up on IP enforcement.