Who would invest in Ilya, though, when he very publicly tried to oust one of his oldest allies and failed? Trust can’t be built that way

Don't forget when he's anti-progress in the real sense of the word. Ilya's brand of idealism flies on hacker news because that's the kool-aid here. But in the real world most people, including investors, are aware that it doesn't matter if your product has ideals when its novelty has plateaued enough that people with actual resources can catch up with a bit of time. Investors are fine piling resources on 2nd best if 2nd best actually has a plan beyond good vibes and doesn't have a history of turning its back on the resources needed to make headway expediently.

Why wouldn't I trust someone who took action to uphold their organizational charter, knowing there would be intense pressure to do otherwise?

Investment is only partially about trust. I agree Sam's a pretty investable guy. I expect Sam to pursue growth through fundraising, product commercialization, corporate partnerships, etc in exactly the YC mode. He's also clearly ok with letting the momentum of that growth overwhelm the original stated aims of OpenAI, especially given what the original firing press release said about Sam not being entirely forthright. I suspect Microsoft made their investment knowing that something like this might happen. It's not trustworthy that he tried to overwhelm nonprofit aims under for-profit momentum, but if you're an investor do you care?