I'm a bit skeptical of technology in general squashing diversity.My understanding is that the advent of the 78 record managed to popularize the Sligo style of Irish fiddling all over the world and across Ireland. Unfortunately, it caused a lot of local fiddlers to just hang their fiddle up, resulting in a tremendous die-off of regional styles. I'm also given to understand that every holler in the mountains of West Virginia had their own style of banjo. There was once a central Pennsylvania fiddle style. All of these have largely died out. (Imagine you meet a cosplayer from 200 years in the future, and their conception of "American" is a simplified homogenized mix of all 19th and 20th century American culture of all regions. This is the degree of squashing of diversity I'm talking about.)
Pre the printing press you could pretty much just get the bible hand written. With the early press far more then as you didn't need type setters more again.
Sure, if you only have that one data point, that's what you'd think. There's a lot more to it. Prior to widespread literacy, there was a tremendous amount of oral tradition and storytelling. Back in those days, if you wanted media, the family or community had to produce it, itself. (In America in the 1800s, it used to be the norm for at least one member of every family to be capable of performing at a level that would get one paid today.) Why would you think all of those would have been written down? In fact, people who study these things know much was lost. We only have a smattering of what once was.
In general it seem better tech -> lower costs -> more diverse.
The tech we had in the Industrial Revolution up through the late 20th century wasn't as interactive and capable of gathering data, and so wasn't as good at serving the long tail. So there was a bias towards only a few things that were mass produced, and unless you did a lot of legwork, that's what you got. As technology progressed, you had easier discovery/access, more customization, and more choices. In 2019, everything is preserved, everything is available if you just casually search for it. The world wasn't always that way.