Nobody can predict how soon a technology will plateau. People make predictions based on insane hot takes like "I pray to our new overloards who will make me immortal" and "there's nothing new under the sun, everything is just marketing"...
There might be the next AI winter starting starting next year, AI might wipe out humanity in our lifetime, even both of those might happen. Both very unlikely (qualitatively) ends of a huge spectrum.
That's not to say that we "don't know anything and thus give up talking about it". Otherwise I wouldn't participate in this discussion and I hope you wouldn't either if you didn't expect to sometimes learn something or be confronted with a new idea.
I just find both attitudes "it's making us immortal" as well as "I'm so experienced, I know that no new technology ever lives up to expectations and can mock people who admit they don't know that" unproductive. You don't know. Most technologies don't live up to expectations, a few work out even much better than expected. I'm sure before the Lee Sedol match, you thought to yourself "right, so it's going to win this and then plateau exactly a decade later"?
There's also no "ruling out" the Earth will get zapped by a gamma-ray burst tomorrow, either. You seem to be talking about something that, if done properly, would require AGI.
You can do anything with AI. Anything at all. The only limit is yourself.