And Microsoft has total rights to the models and weights, so they can CONTINUE their services and then spin up with Sam's new company.
I think it's reasonable to assume that even a controversial board checked with their lawyer and did what was legally required. Especially as nobody involved seems to be claiming otherwise.
Having no information on what laws and governance documents apply to OpenAI or on what steps the board took, I express no opinion on whether the legal requirements were actually met, but it’s possible they were.