The LLM bubble may fizzle rather than pop in any dramatic fashion, but it's certainly not the last word in AI - much more the exact opposite.

We've had AI "bubbles" / hype-fests before (expert systems, Japanese 5th generation systems), and I don't expect this will be the last.

There will also be technology bubbles and hype-fests in the future outside of AI - it's human nature. Hard to predict what they will be of course (the future is like that).