How could we judge if anyone is "winning" on cost-effectiveness, when we don't know what everyones profits/losses are?

If you're trying to build AI based applications you can and should compare the costs between vendor based solutions and hosting open models with your own hardware.

On the hardware side you can run some benchmarks on the hardware (or use other people's benchmarks) and get an idea of the tokens/second you can get from the machine. Normalize this for your usage pattern (and do your best to implement batch processing where you are able to, which will save you money on both methods) and you have a basic idea of how much it would cost per token.

Then you compare that to the cost of something like GPT5, which is a bit simpler because the cost per (million) token is something you can grab off of a website.

You'd be surprised how much money running something like DeepSeek (or if you prefer a more established company, Qwen3) will save you over the cloud systems.

That's just one factor though. Another is what hardware you can actually run things on. DeepSeek and Qwen will function on cheap GPUs that other models will simply choke on.

I believe this was a statement on cost per token to us as consumers of the service

Well consumers care about the cost to them, and those we know. And deepseek is destroying everything in that department.