The "Dead Internet Theory" is too sad and too easy. I'd propose the "Dead Society Theory", the history of the Internet from the late 2000s to the late 2010s left people socially scare, paranoid, angry and hopeless about the possibility of communicating online.
Which is to say the Internet can be "dead" without being filled with undetectable or detectable fake posts, not that fake posts help things.
Which is to say the Internet can be "dead" without being filled with undetectable or detectable fake posts, not that fake posts help things.