The concept of cryptocurrencies is based on trust. If it is fully implemented in all aspects, there is trust within the community and technical solutions applied to provide the security of network, then there will be no need for centralised control.
Got your point. But what about security? I constantly hear about hackers who steel tons of investor's money...
And goverment won't give up its influence easily. USA, Canada and some european countries tend to establish their rules on cryptocurrencies.