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.

IMHO, the theory is wrong. There is tons of real, human interactions online. I see it on reddit constantly. The bot activity is easily ignored or algorithmically suppressed most of the time.

If the dead internet theory were true or real, Google and Facebook would not generate so much revenue. Advertisers would notice that they are not getting any conversions and stop spending.