#4 Bitcoin mining is indeed centralized. Too much for sure, and other aspects of the network should also be more decentralized. But that is not its job: that is your job. This natural money is just a method of securing transactions economically and globally. How those transactions are carried is a different story, maybe yours.

We just need ways to transfer those bytes accross the houses, streets and the globe, a pretty simple task isn't it? Satoshi Nakamoto set already the right path by "the network is robust by its unstructured simplicity" and "messages only need to be delivered on best effort basis".

It is up to us to implement the best strategies for this.