From my naive perspective, there seems to be a plateau, that everyone is converging on, somewhere between ChatGPT 3.5 and 4 level of performance, with some suspecting that the implementation of 4 might involve several expert models, which would already be extra sauce, external to the LLM. This, combined with the observation that generative models converge to the same output, given the same training data, regardless of architecture (having trouble finding the link, it was posted here some weeks ago), external secret sauce, outside the model, might be where the near term gains are.

I suppose we'll see in the next year!