You reap what you sow.

Perhaps this could be mitigated by making the deployment process simpler, ie: a single static binary to download and run instead of having to set up a million different services and edit a million different configuration files. But then again, as long as there is any friction to the setup process, there will be centralization in the form of large servers, as users will go down the path of least resistance.

I guess the real solution here is to simply abandon the concept of federation all together and instead use a peer-to-peer (p2p) model. A p2p model would completely alleviate the problem of centralization by enforcing decentralization, by simply removing the possibility of centralization using design.