Just a quick reminder that the pure nr of nodes is not the most important thing here. F.ex., if all nodes run on AWS, or run by a few companies/entities, that's still a central point of failure, even if there are many nodes. Geographical location is somewhat important as well - not only to avoid points of failure but also influental on propagation times (although I'm not sure if that's actually true or not, and even if it is, it's probably only about milliseconds).

One could even argue for importance of nodes distribution between different cultural groups, but here we would be already entering some rather philosophical grounds, I guess.