I don't think AI really solves the problem. The question "What happens when sensible humans are no longer at the helm?" really means "What happens when people with different priorities are at the helm?" It's totally possible for a sane being, artificial or not, to take over Patreon and prioritize profit, or enforce their own values, or even shut down the site.

The core problem is that you're interacting with entities you can't control. It's almost tautological; if you can't control them, by definition they can do things you don't like.

I've only read the first Culture book, but I'm pretty sure the Idirans didn't feel like the Culture AIs were "sensible".