Let's work through this statutory licensing concept.

A work is published. Sometime later, the entity that created it falls off the face of the earth. The work is thus very much abandoned, and it remains copyrighted anyway.

But tomorrow, that work will enter the timeframe where anyone can pay to license and publish it however they wish. And it just so happens that you wish to license this work and publish it as an ebook because you're feeling trite or something.

Who do you pay? How do you pay them?