That’s a pretty common urban legend about egregiously overdue books. They typically don’t keep accruing fines for years and years. That legend was most famously explored in the 3rd season of Seinfeld when Jerry has a library fine from 1971. In fact, most libraries stop keeping track after a while, consider the book lost, and buy a replacement. BC Libraries charges no more then $100 in the case that someone never returns a book (see bit.ly/BCLibraryFines for more detail). Of course, some materials are irreplaceable: in those cases, the material is usually in an archive and not allowed to leave the building or a special reading room for exactly that reason.