It is claimed by some, DPOS is not centralized. Steemit operates on a system of 20 witnesses plus another 100 or more witnesses.
The claim then is, "See, there are only a 100 points of failure! Take down the 100, and the system collapses." It's a true statement, but the argument neglects how centralized Bitcoin and Ethereum has become with the centralization of mining pools and professional mining operations.
This was a criticism Vitalik brought against DPOS and EOS recently, and I elaborated this point of Ethereum centralization fully. My conclusion was that perhaps 30 points of failure exist for the Ethereum protocol, to determine what it is, and it's future. Something like EOS when it launches would have perhaps 60 to 120 points of failure.
The argument of Bitcoin and Ethereum having widespread decentralization is really not a true argument, but it's the main argument brought against DPOS.
https://steemit.com/eos/@crypto-investor/centralization-of-cryptocurrency-bitcoin-ethereum-and-eos