One of the big mistakes people make, over and over again, is relying on technological determinism.
That is, thinking the architecture of the technology will preserve the topology of the network.
Mastodon is Open Source. It's built with open standards.
This is necessary but not sufficient to keep the network decentralized.
We're going to need social and legal structures, plus cultural norms, that counterbalance Metcalfe's law, which pushes the network towards centralization.