Counting on piracy means we will lose stuff. By definition, piracy has adversaries whose job it is to stop it. We cannot count on pirates never to lose any single cultural artifact because their existence is adversarial. Archives and libraries do something legal, they keep culture alive for future generations. Waiting 90 years to obtain the right to make copies is a tradeoff. The point of libraries and archives is not to give you web access to every rom with a single click, it's to preserve culture. Access is a bonus, not the point. That's why most of a museum's collection is in their vault. What Archive.org is doing is with their collection is a compromise, and is actually criticized by many other archives who see their adversarial stance with copyright owners as detrimental to the mission of preservation.