Central bank? Inflation via derivatives? No, Bitcoin can't be centralized and dissolves the government power necessary to enforce the perverse incentives that created the present fiat money derivative situation.
Bitcoin can't be centralized? Now I'm not sure what you mean by being centralized. Look, I already encountered two contradictory ideas about what Bitcoin decentralization actually is, so what is your take on this? If someone grabs more coins than anyone else, would this go for centralization? Or, rather, what could in this case prevent their owner from inflating Bitcoin derivatives if he decides to?
It's a long story if you're not familiar with Austrian economics, but as far as one person or group amassing too many coins, it can't happen for very long. Even if one guy magically had 90% of all coins, he could only enjoy this situation to the extent that he spends them.