That would've greatly harmed their investment Now they get to have their cake and eat it too: they can keep their existing relationship with open AI and continue to get access to their models, and yet at the same time they potentially get all the best people in-house and benefit from their work directly. This whole turn of events might turn out to be a net win for Microsoft.
I'm of the mind that CEO's are like parents, an awful CEO can cause a lot of harm but the difference between an ok CEO and an excellent one isn't that big and doesn't guarantee anything.
Given that the OpenAI board has to act via mandate from its non-profit charter, what's the likelihood that this was Microsoft's plan in the first place? E.g. getting Sam to be less than "candid", triggering a chain of events, etc.
Even if Sam deliberately provoked them and this was a set up, no normal person would be this obstinate about it. They would’ve given up now if this was anybody’s doing but their own.