It took a while to be especially effective, both because techniques of propaganda had to be learned, and because the general populace was not literate. As of 1500, population literacy rates in Western Europe were on the order of 10--25%. The climbed to 90%+ in the 19th century, the midpoint of which saw rapid advances in printing technology (iron presses, powered presses, web presses), a sustainable business model (advertising, as it happens). And in the year 1848, Europe basically exploded into revolution, affecting over 50 counries:

https://en.wikipedia.org/wiki/Revolutions_of_1848

More generally, the role of the printing press as an agent of change (social, political, economic) is the subject of Elizabeth Eisenstein's book of the same name:

https://en.wikipedia.org/wiki/Elizabeth_Eisenstein#The_Print...

https://www.technologyreview.com/2021/09/16/1035851/facebook...

Stuff like this was impossible before.

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...

Newsstands contain dozens of newspapers, typically all owned by only 1 or 2 conglomerates. How is that any different than a Facebook feed which shows hundreds of groups spamming out propoganda, all of which are operated by a much smaller number of entities?

A bit different eh? It's unaccountable bad actors on the other side of the world.