“... sola scriptura “Bible Christians”....”
So far as I know, there were no “sola scriptura” Christians, oppressed or otherwise, until, at the earliest, the Protestant Revolution.
Few things in history have had the impact that the invention of the printing press had. The Protestant Reformation COULD NOT have happened with the printing press because their entire doctrine is predicated upon each person being able to read the Bible.
Prior to the 16th century books simply weren't available except to the VERY WEALTHY. Very few people could read, not because learning was suppressed, but because there was nothing for them to read (and it didn't matter that no Bibles were in the vernacular because EVERYONE who was able to read could read Greek and Latin).
My opinion has long been that the Protestant Reformation was a foregone conclusion. It was going to happen, it was just a matter of where and how soon. Martin Luther wasn't the first person to come up with new ideas, but he was the first person with the technology available to disseminate these ideas throughout Christendom regardless of attempts to suppress them.