that literacy is what would allow the working class to take over running a society. The issue of illiteracy preventing revolution would therefore be mitigateable by a literate vanguard party that after the revolution set about mass literacy programs.

Hard disagree, if anything that makes conditions dire enough revolution becomes all but mandatory.

The Internet and the ability to vlog might be an X factor that Marx didn't account for. Not that I'm not talking out of my ass, but it is a method of relaying information that Marx didn't have

I would argue akin to Vietnam, the early leftist movements in the US didn't have the benefit of high literacy amongst the working class. As a result you have a lot of leftist folk music traditions where a song writer would take a popular song everyone probably knew, changed the lyrics, and then sang it and helped people learn it. The Preacher and the Slave, Dump the Bosses Off Your Back, or the pretty obvious 3fer of John Brown's Body, The Battle Hymn of the Republic, and Solidarity Forever.

Utah Phillips explains it pretty well in the opening of Dump the Bosses Off Your Back

If workers become illiterate and lose access to the ability to reproduce society thats game over,

Kinda reminds me of slavery but in reverse

Instead of enslaved people becoming increasingly educated and more demanding of freedom, free people become increasingly illiterate and closer to a slave-like status