The three things cited in the post summary? Never been on them. I never ever heard of one of them. It seems to me that it's more that these few platforms are struggling, and other (twitter/x, reddit, facebook, and other) just keep sailing smoothly.

I don't post because I know no one will see my posts, and I don't want to give them my data without feeding my narcism in return.

I deleted all my big tech accounts, and lots of people are posting on the fediverse.

Social media was fun until my family joined and scrutinized my posts, and then I lost all my friends

Good. Let it die.

Twitter's so annoying, they constantly show me the same ads. Was it different before Musk?

Noticed this on reddit's All/Hot in the last two years or so. Not even just the posts but the comments in particular were very Bot-like. Front page was almost all recycled reposts and thinly veiled marketing.

Before doing Lemmy full time I scrolled through Red with the official app just to see if I could compromise somewhere, but it smelt of Dead Internet to me.

Dead Internet Theory in short is a conspiracy theory that most of the Internet is just algorithms and bots posting back and forth at each other for marketing purposes and to nudge people's beliefs. It's dead because theres hardly any humans posting.