Approximately 140 million books have been published in all of modern history. Between 600,000 and 1 million new books are published each year. This year I am on track to read more than 100 books, but in a normal year I read about 50 or so. At that rate, if all new publication ceased, it would take me about 2.8 million years to read every published book.
I might have to pick up the pace somewhat.