Many tasks are amenable to simulation training and synthetic data. Math proofs, virtual game environments, programming.

And we haven't run out of all data. High-quality text data may be exhausted, but we have many many life-years worth of video. Being able to predict visual imagery means building a physical world model. Combine this passive observation with active experimentation in simulated and real environments and you get millions of hours of navigating and steering a causal world. Deepmind has been hooking up their models to real robots to let them actively explore and generate interesting training data for a long time. There's more to DL than LLMs.