> D) Bitcoin is still, objectively, centralized.
Not only you, but this whole thread is missing one critical word: incentive.
Miners are incentivised to play ball, as trying to play games will result in the rejection of their hashing work. Wherever they are, it does not matter (up to a point, ie geographical risk repartition). But in actuality, we know there are miners all over the planet, and that there are thousands of them.
Parenthesis: by the way, non-mining full nodes add precisely ZERO value to the network, and they actually slow it down. Before you guys start yelling, please see reference at the end of my comment for details. That's another urban legend purported by Bitcoin Core. Anyways, don't get me started.
OK, back to miners: yes, as time will pass, there will be mining consolidation, it's inevitable. But it will not matter. In addition to miners, there will be large service providers (thousands of them) who will be -incentivised- to run either small mining nodes (more secure) or non-mining nodes (less secure) for verification of their own transaction. That alone will be more than enough to ensure the security of the network.
From the start, Satoshi was predicting the apparition of large mining server farms, no farther than in the very FIRST email he wrote to the world!!
http://satoshi.nakamotoinstitute.org/emails/cryptography/2/#...
quote: At first, most users would run network nodes, but as the network grows beyond a certain point, it would be left more and more to specialists with server farms of specialized hardware. A server farm would only need to have one node on the network and the rest of the LAN connects with that one node.
Bitcoin Network Topology Description (provides visual explanatino as to why non-mining nodes are totally useless, and even detrimental.
https://fr.scribd.com/document/359522859/Bitcoin-Network-Top...