There are a lot of leaps of faith baked into these scenarios. It appeals to fundamentally religious instincts. Notice that people start with a seemingly sensib

There are a lot of leaps of faith baked into these scenarios. It appeals to fundamentally religious instincts. Notice that people start with a seemingly sensible set of propositions, and what falls out is the Apocalypse, immortality, heaven (or AI hell) and a sense of urgency, up to and including passing the collection plate. Since you asked about the argument for recursive self-improvement goes like this. Say Alice is a human engineer, who designs an AI (Bob) who is her intellectual equal. Then she can run Bob on faster hardware, and the now-smarter-than-her Bob can repeat the trick to design Clara, and so on. It's AIs all the way up. If you're a certain kind of beardo, you imagine this process could be compressed into a few hours.