LLMs allow us to do large but cheap experiments that we would never attempt otherwise. That includes new architectures. Automation in the traditional sense is opposite of plasticity (because it's optimizing and crystalizing around a very specific process), but what we're doing with LLMs isn't that. Every new request can be different. Experiments are more possible, not less. We don't have to tear down years of scaffolding like old automated systems. We just nudge it in a new direction.
Eventually, prog-lang designers will figure out how to get llms to create new prog-langs.