source: http://www.regionalpropertynsw.com/property-insights/decentralisation

Are cryptocurrencies really decentralised as they promise?

Decentralisation is a buzzword that almost every cryptocurrency is claiming to be. But is this really the case?

And what the hell is decentralisation anayway?

• In short term: Your data is not stored/processed on a single device, but on more than 1.

What is this good for?

• Higher hacking resistance, because it would be necessary to hack all or the majority of the devices holding your data.
• Data redundancy.

Why are some cryptocurrencies more decentralised than others?

That depends on how transacation are being processed/verified. Today most cryptocurrencies using blockchains are based upon on

• proof of work (PoW) - transactions are being verified by computers (miners)
  or
• proof of stake (PoS) - transaction will be verified by a node randomly selected computer (node) by an algorythm

That makes system based on PoW vulnurable. Its most prominent member is Bitcoin, which XRP-CEO Brad Galinghouse stated to be controlled by China, because the most 4 powerful miners in China combined do have more than 50% of the hashing power of the Bitcoin network and so the majority.
source: https://de.cointelegraph.com/news/ripple-ceo-claims-bitcoin-is-under-control-of-small-group-of-miners-from-china

That being sad Bitcoin is decentralized, but what if thise 4 miners are decide to cooperate? They together could begin altering the blockchain in the way they like. So from this perspective Bitcoin is relatively centralised. Just think about it for a second.

But of course the same can happen to a PoS where all or the most nodes are controlled by one person (e.g. NEO).
In PoS-systems where nodes are elected by the coin holders (e.g. EOS) the people with the most coins do have the most voting power. And in most cases the rich are getting richer over time...

So is all hope for true decentralisation lost?

There might be a light at the end of the tunnel by the name of IOTA. In my opinion IOTAs system is way better than PoW and PoS as we know. There are no almighty miners and there is not a bunch of nodes able to take over the network. Their network is called "Tangle" and it is based on PoW. Wait a minute you will say. You just told us that PoW is crap. Please let me explain.

In principal PoW is not that bad. What makes it problematically is when few computers have superior hashing power. IOTA is trying to solve this problem with making all participants of the network to miners of equal power. If you want to make a transaction on the network you have to verify 2 other transactions first and so on.

What about fees? There are no fees on the IOTA network. Instead of paying fees you have to verify 2 transactions like mentioned above. So there is no money to make for miners and nodes with IOTA. So happy new world? Unfortunately not. Sadly IOTA is only working for sending/recieving payments and not with smart contracts etc.

Conclusion: A mixture of IOTAs Tangle system (non profit) and blockchain could be an answer. I dont know any project out there having a solution right now. Maybe you know? Please tell me.