Because AGI is still some years away even if you are optimistic; and OpenAI must avoid going to the ground in the meantime due to lack of revenue. Selling ads and believing that AGI is reachable in the near future is not incompatible.
For years now, proponents have insisted that AI would improve at an exponential rate. I think we can now say for sure that this was incorrect.
Did they? The scaling "laws" seem at best logarithmic: double the training data or model size for each additional unit of... "intelligence?"
We're well past the point of believing in creating a Machine God and asking Him for money. LLMs are good at some easily verifiable tasks like coding to a test suite, and can also be used as a sort-of search engine. The former is a useful new product; the latter is just another surface for ads.
That is, shall we say, not yet proven. But it's not yet disproven exactly, either, because the AIs we have are definitely not yet smart enough to meet the starting threshold. (Can you imagine trying to let an LLM implement an LLM, on its own? Would you get something smarter? No, it would definitely be dumber.)
Now the question is, has AI (such as we have it so far) given any hint that it will be able to exceed that threshold? It appears to me that the answer so far is no.
But even if the answer is yes, and even if we eventually exceed that threshold, the exponential claim is still unsupported by any evidence. It could be just making logarithmic improvements at machine speed, which is going to be considerably less dramatic.