Artificial Intelligent Chatbots - What's Changed?

The idea of making a chatbot that is indistinguishable from a human has been the holy grail for people in this area. Was there a specific technological breakthrough or some kind of new technique that made this possible? I think what's changed is that this became publicly available on November 30th of this year and the rest of the world got to try out it. It's not like chat GPT is the only technology of this sort. There's a lot going on with large language models which this is to imitate human writing and human speech.