Variability of Decentralization in Distributed Ledger Technologies (DLTs)
Distributed & decentralized systems are not interchangeable classifications. While decentralized systems (i.e. blockchains) are a form of distributed system, not all distributed systems need to be decentralized.
Decentralization refers directly to decision-making power, not how dispersed the network of the system is. So, decentralization can differ quite significantly when considered distributed ledger technologies (DLTs). In addition to blockchains, here are three other examples of a DLT:
Directed Acyclic Graph (DAC)
DLTs are a type of cryptographically secured record of consensus that has a consensus trail validated by a series of network nodes. Those nodes work together to validate that the record of consensus is consistent with the status of the network. A key point here though is that all nodes on a DLT network do not necessarily need to be equal.
Nodes can have designated rights on the network that differ in the amount of permissions they have. In other words, the amount of decentralization on a DLT network can vary substantially depending on how permissions are given to nodes on the network.
In a centralized distributed system, there may be a small series of nodes that have all the information about the network. This gives those nodes a complete picture of the record of consensus and gives them the highest amount of decision making power over the network. The remaining majority of nodes may only be given access to a refined dataset, giving them less information overall and lower decision making power.