Assuming we take this at face value, once you have a lot of money power becomes appealing - and control over a very important player in the AI space is that. The original vision of openAI was democratization of that decision-making process, the model now is - these guys are in charge. Maybe that's altruistic, because they're the smartest guys in the room and they can mitigate the downside risks of this tech (... not fucking AGI, but much more like the infinite propaganda potential of chatGPT). I'm more a fan of democratization, but that's not a universally held opinion in sv.
What do you do with excess funds? Invest it? Direct it towards your interests and achieving your ideas? If you set up the organizational structure such that you are unlikely to lose your power over it unless you choose to, do you or do you not have similiar control over the equity as if you owned it?
Some people have technology visions which they direct their capital towards. I sense his interest is actually a mix of cultural and social. Is it altruistic? Maybe, but maybe not... It's probably more useful to consider if the vision is or is not restictively utopic and if you think it should or shouldn't be orchestrated / heavily influenced into existence from a central power structure. Is his vision and approach socially aligned?