The question isn't "was this specific level of capabilities available previously" but "did the introduction of new media technologies significantly disrupt the cultures into which they emerged?"

And the case that Eisenstein makes, at book length, is "yes".

She's building off earlier work (notably McLuhan's The Gutenberg Galaxy), and you can find numerous prior and subsequent references.

I've copiled a few here: https://old.reddit.com/r/dredmorbius/comments/7k7l4m/media_a...