The argument I keep seeing is that once they can reduce the spend on R&D (training new models) they will be wildly profitable.
The thing is if models become 'good enough' that the main value is in running existing models, those will quickly proliferate and be available for commodity cost from many competing providers. Why pay Anthropic when I can just pay AWS or Azure directly to run whatever future version of Qwen does the job for me?
If the value actually remains in the frontier models, you can't stop spending on training new ones or you'll eventually be left behind by your competitors and they'll capture that value.
I haven't yet seen a good explanation of how companies like OpenAI and Anthropic will make the transition to a lower cost structure while maintaining the revenue that they currently get for being on the cutting edge of LLMs.