When you talk to young folks, they think that the belief in imminent AGI was caused by the rise of LLMs. In reality, this belief is axiomatic and long predates LLMs. DeepMind, Vicarious were founded in 2010 based on this belief. OpenAI in 2015. Interest in LLMs only began in 2019.
In 2015, when deep learning was in its infancy and LLMs were years away, many folks were just as convinced that AGI was around the corner as they are today. The only thing that changed is that people are now anchoring these beliefs on LLMs, whereas in 2015 they were looking to Deep RL, LSTMs, and Neural Turing Machines.