Foundations, like companies or any organization, are composed of people. People can and do get replaced, corrupted or bored and move on, they can eventually decide to take the organization in a direction unlike what was originally intended. Takes more time and effort than just throwing a pile of money at the founders and shutting it all down, of course.
Is this likely? No. Is this a single point of failure? Yes.
All the internal federation in the world does not allow me to pack up and move while still chatting with my old contacts.