Anthropic/OpenAI and the investors are the same thing. A company name is just a title for the people who own it.

Maybe you mean that you could see the employees of those companies (although I imagine they also own it, so that's a wrinkle) staging a coup to seize the army for themselves? That's certainly possible. They'd be in a good position to do so. Predicting the future is impossible, but if you want to be on the "right side" of that future army, owning its foundation today is still a reasonable bet.