Your figures assume that the "scraped from the internet" means a randomly sampled scrape. If the nudenet dataset grabbed those images from say, 4chan, one would expect the percentage of csam images to be higher than that of Twitter. I don't think you can draw any reliable generalities about the prevalence of csam on the internet from this. I don't know what the actual figure is, but that seems far too high to be accurate.
The review in your example is useful if I'm looking for a game with crocodiles, or I'm looking for a game without crocodiles. That is evaluating the game, just with narrow criteria.
Tranquilizer dart guns are not common. But they are essentially the same as pellet guns, just with larger bores, obviously. These can be very quiet, depending on how powerful they are. You could definitely still hear them at a few meters away, but the sound would not be recognizable as a gun.
They have gotten them to generate power, by which I assume you mean give off more energy than was used to create the reaction. But they haven't gotten them to sustain that.
Your figures assume that the "scraped from the internet" means a randomly sampled scrape. If the nudenet dataset grabbed those images from say, 4chan, one would expect the percentage of csam images to be higher than that of Twitter. I don't think you can draw any reliable generalities about the prevalence of csam on the internet from this. I don't know what the actual figure is, but that seems far too high to be accurate.