The game theory logic doesn't care about the labels "OpenAI" or "Anthropic" or any of the others, it's the same if you switch it around arbitrarily, but this is easier to write about if I focus on one of them:

At some point, someone will reproduce GPT-3.5 and ChatGPT, given how much is known about them. When that happens, OpenAI can't make any significant profit from it. GPT-4 might remain sufficiently secret to avoid that, but the history of tech leaks and hacks suggests it too will become public, but even if it does itself remain behind closed doors, there is a further example in that DALL•E 2 is now the boring 3rd horse in the race between Stable Diffusion and Midjourney, and the same may happen with the GPT-series of LLMs.

The models leaking or being superseded by others implies profit going to increased productivity in the general economy without investors getting a share.