Recursive self improvement - once you attain artificial superintelligent SWE of a general, adaptable variety that can scale up to millions of researchers overnight (a given, with LLM's and scaffolding alone) - will rapidly iterate on new architectures which will more rapidly iterate on new architectures, etc.
From the first third of a sigmoid it looks exponential, and that scares people. But a sigmoid can have a very very high top - look at the industrial revolution, or modern plumbing, or modern agriculture which created a population sigmoid which is still cresting.
If AI is merely as tall a sigmoid as the haber-bosch process, refrigeration, or the steam engine, that's going to change society entirely.