Why do people on this sub seem so much more confident in their predictions than everyone else? It feels like more than 90% people here believe that there's a very good chance of AGI appearing before 2040, while in real life and other subreddits it's probably the complete opposite. What is it that people on this sub know that nobody else in STEM is aware of?

Depends on what their religious beliefs are. I was born in a Muslim family and I was very pious, until I came to the conclusion that a sincere belief in Islam is incompatible with 'belief' in science. One of the central tenets of Islam is that this world is temporary and the goal of a human ought to be to please God so as to gain entry into paradise in their afterlife. And so I don't think that it's possible for a Muslim to stay faithful whilst also being heavily invested in technological advancements, because if he believes in Allah then he should be following Allah's commands and worshipping him 24/7 in the hopes of being granted paradise.

But that's my personal opinion. There are millions of Muslims who are perfectly able to reconcile their belief in God with their interest in technological advancements. Good for them. I can't do that. But if I was born in a family that believed in a God that doesn't interfere with his creation, maybe I would have still retained my faith.

Your last post was on r/astrologychartshare. I didn't know this sub had people that believe in astrology.