This is corporate speak for "LLMs have hit a wall". I mean, it's been obvious for a bit, lately nearly all gains have been from harnesses (or whatever you want to call all the non-LLM bits that make up a chatbot or agent).

If Anthropic and OpenAI were still seeing exponential or even linear gains from scaling they'd be doing it because the rewards to reaching AGI or SGI before everyone else are basically infinite. If both are talking about slowing down it means there's no known path to AGI so they're both going to push the safety angle as an excuse to slow down training new models and take profit.