Aren't they proving the opposite of your proposed alternative already? A limited AI is not making them money and since every new model becomes obsolete within a year, they can't just stop and enjoy the benefits of the current model.
OpenAI valuation is reliant IMO on them on them 1) AGI possible through NNs, 2) them developing AGI first and 3) it being somewhat hard to replicate. Personally I’d probably stick 10%, 40%, and 10% on those but I’m sure others would have very different opinions or even disagree with my whole premise.