You say it is not so different from a centralized system that has replicas in multiple data centers.
- if we speak about bitcoin nodes: don't forget that centralized systems can be shut off very quickly by governements
- if we speak about miners: new mining pool software is just being developed (and some of if finalized), that takes away power from pools, and gives it to the many small miners:
https://medium.com/hackernoon/betterhash-decentralizing-bitc...
and
https://www.reddit.com/r/Bitcoin/comments/ci2daj/making_mini...
1. Governments need only to track one blockchain to track every BTC transaction. Attempts to deal with this mainly entail coin tumbling, which involves giving your coins to a centralized trusted entity. Larger tumblers are more effective, creating an incentive for further centralization.
2. The central blockchain is a performance bottleneck to event throughput. Attempts to deal with this mostly have to do with federation, i.e. forcing people to transact through another entity (usually a company you pay fees to) if they want faster transactions. Federation is much closer to centralized on the centralized/decentralized spectrum. Usually companies respect regulation from centralized government (meaning a government could force them to not process your transactions) increasing centralization further. And historically, federation happens unevenly, i.e. a large number of email users federating under GMail, which creates further centralization.
3. Mining competition has a very high entry cost because the minimum investment for entry is very high. The solution to this is pools under a centralized pool manager who typically collects fees and may or may not collect data on pool members.
>> - Political decentralisation: how many people or entities are in control of the network?
>> - Logical decentralisation: does the whole system behave like a single entity?
>> The take away from Vitalik article, is that all blockchains combines these three dimensions into one system.
Actually, Vitalik states in his article that individual blockchains are logically centralized: https://medium.com/@VitalikButerin/the-meaning-of-decentrali.... It depends on whether we're talking about a specific blockchain or the set of all blockchains. That's why I don't agree with the position of Bitcoin maximalists; their vision is not fully decentralized. When you factor in the centralization of mining power, BTC is only architecturally decentralized. Bitcoin is not so different from a centralized system which has replicas in multiple data centers.