It's not so much dead people +Liam Phoenix
as abandoned interest. Majority of printed works pass into the void unnoticed, but copyright is held essentially in perpetuity. Searching for copyright holders, even if you want to pay them is ususlly fruitless. In such cases, the should be a way to republish materials of public interest. For example, a cache of jazz recordings from the 30s, 40s and 50s was revovered a couple of years ago. Although it can be made available at an academic library, none of it can be republished. Most musicians and other holders cannot be identified and, even if they could, their heirs cannot be found. This is a classic case of copyright law being counterproductive -- doing exactly the opposite of what it is constitutionally required to achieve.