What, if anything, would be different in todays society if the Library of Alexanderia survived?
The Library of Alexanderia was the first library that was for all people of the time, (it is thought to be built in Alexanderia, Egypt approximately 325 bc), holding 300,000 - 700,000 scrolls and manuscripts. Complete works of Socrates, Seneca, Cassius, plans of the Lighthouse of Alexandria, Hanging Gardens of Babylon (and other writings of the wonders of the ancient world), the science and use of steam, astronomy, medicine, philosophy, and, believe it or not, electricity. The library was burned in the 3rd century, then submerged into the sea by earthquake and tsunami. Amazing stuff.
Sadly, outside academia, I don't think things would be much different. We would have more historical knowledge than we do today, but we already have a great deal of historical knowledge that most people ignore or don't use for anything.