Considering the exponential increases in invention and adoption of new technologies for the past 200 years, I'm not sure that timeline is very close to what I'd expect from a new technology in this era.

I'd argue that we've already passed peak LLM as I think, after been having burned by it a few times, it's usage as a professional or reliable technology has seceded, rather than accelerated, over the past 6 months. Gone are the days of doom sayers talking about AGI taking over the world and LLMs replacing every single job at the call center and in software teams. Now everyone's scaled back to the things you can actually let it do, which is assist with a lot of coddling/verifying.