You are ignoring technological change over time. As you go back in time, the time and effort to make copies goes up, the costs of distribution goes up, and the speed of distribution goes down. All of those raise the natural advantage that the original producer has over copiers.
For example, when Charles Dickens was writing and publishing his novels in serial form in magazines he didn't have any significant problem with unauthorized copies in the United States even though at the time the United States copyright law did not cover imported foreign works such as his.
That was because by the time the unauthorized publishers got a hold of the next chapter and could get started with the typesetting for making their own copies, the authorized copies for the United States were already sailing across the Atlantic. They makes of unauthorized copies would have to wait for another transatlantic sailing to get theirs to the US.
The result was Dickens' authorized copies were the only ones available in the US for something like a month or so. By the time unauthorized copies could make it over, something like 95% of the people who were interested in the story had already read it in the authorized magazine.
Google "The Uneasy Case for Copyright" and you can find an essay by United States Supreme Court Justice Stephen Breyer written in 1970, when he was still an academic, arguing that these kind of natural advantages of being first to market had generally been enough incentive for creators. There have been a couple essays in response too, which should show up on that search.
