The emergence of a print book market lowered the bar of entry for authors and gradually began to render traditional filters and constraints on the production of books increasingly inadequate. The perception of an excess of books was motivated by a more basic assumption about who should and should not write them.
If the above sounds familiar, that's because it's meant to. It's taken from a text called "Why Google Isn’t Making Us Stupid…or Smart" by Chad Wellmon (via). Wellmon argues that current concerns about digital information overload and the internet making us shallow are overblown, as can be seen from the fact that similar concerns emerged when printed matter became more widely available due to technological advances.
You've probably seen that line of argument before: Today people worry about gangsta rap, but they also worried about rock'n'roll. Today people worry about violent video games, but they also worried about violent television when it was introduced. Etc.
When you think about it, the argument doesn't make a lot of sense. Or, for it to make sense, you'd have to provide much more. Take the books-internet analogy. The claim to be supported is that the internet is not making us shallow. The evidence provided is that people had the same worries about books. There are two links you have to provide to connect the claim and the evidence: (i) the old phenomenon - emergence of printed materials - is identical, or at least similar enough, to the new phenomenon in all relevant respects; (ii) the change that people worried about did not actually materialize - e.g., the abundance of printed matter did not lead to people being more shallow than they otherwise would have been. Good fucking luck with those two! And remember that you need both!
Regarding the second of those, all that's usually provided - implicitly more often than explicitly - is that the world didn't fall to pieces. You could call it the Argument from the Absence of Apocalypse. The funny thing here is that Wellmon and others who reason similarly tell us not to worry about change on the basis that the world didn't experience an apocalypse in the past, and that very fact is also used to argue that we should worry about change. Conservatives tell us that we should be careful changing features of society that "have stood the test of time", as their passing this test shows, or at least suggests, that they're high quality. I have called this the Basic Conservative Fallacy, because all that's actually been shown is that a society which exhibits feature X can survive.
Progressives say, in effect: look, we survived changes in the past, so new ones should be fine. Conservatives say, in effect: look, we survived stability in the past, so we shouldn't change. Both arguments are poor. I'm afraid you'll have to go to the trouble of assessing the consequences of specific changes up front. We're not very good at that, but I don't see an attractive way around it.