I don't think your counterpart is arguing that OpenRouter created DeepSeek. Rather I suspect their argument is that there are 13 providers listed on OpenRouter for DeepSeek v4 Pro that are competing on price. (That's the default balancing algorithm in OpenRouter, roughly: weighted towards the lowest price and was available in the last 30 seconds)

If any providers are able to turn able to sustainably turn a profit, OpenRouter allows them to compete in an open market to process your tokens (or anyone else's tokens).

Thus anyone subsidizing tokens bears the brunt of the compute load and gains not much more than name recognition and tokens to train on, but since switching to a different provider is a matter of changing one setting in the config panel (and can be set to auto-switch based on price), switching costs are very low. Providers of open models via OpenRouter have almost zero ability to lock-in users.

So this claim that all 13 providers are selling subsidized inference is... a tough claim to swallow. Maybe some of them are, but all of them? I assume at least some providers want to show profitablity, and are pricing their service accordingly.

https://openrouter.ai/deepseek/deepseek-v4-pro/pricing

https://openrouter.ai/docs/guides/routing/provider-selection