The problem is that OpenAI will have to keep doing this basically indefinitely, as otherwise open-source commodity models will catch up with them and offer an equivalent product at a much lower cost. If the company is reliant on having to keep paying more than it's making on its current model to train new models, I don't see how it can ever become a sustainable business.
Not even just open source models - other commercial LLM models as well. All of the big LLM companies (Google, Anthropic, OpenAI) are basically ocked in a cold war of having to continuously outspend the other providers or risk becoming irrelevant.
The big question for me is if people will ever be happy with a model that is "good enough", and can thus be optimized and run profitably over time without faling behind. Time will tell!
The bigger question is if you have a model that is "good enough" that is open source if there is a market for APIs delivering said models that able to justify the funding.