The question of how miners will be paid in the long run, after mining subsidy rewards disappear is a much debated topic in Bitcoin. For those who don’t know, mining rewards are set to half every 4 years until they finally reach zero sometime in the year 2140. How the Bitcoin mining ecosystem will remain profitable (and thus healthy) is up in the air. Miners are important as they provide security to the Bitcoin network because they convert real world energy into network security to guard against attacks from malicious forces. Therefore, the more decentralized and diverse a mining ecosystem is, the better for Bitcoin.
So what will happen when mining rewards disappear? Well, some miners feel that transaction fees should rise up to fill up the shortfall. As Ang Li puts it from an excerpt of the a recent article at Bitcoin.com
The incentives that Satoshi Nakamoto designed in the Bitcoin whitepaper are not enough to sustain mining for long, Li feels, adding that as the block reward halves every four years, miners income will continue to decline. According to him, keeping the block size where it
is now will not provide enough incentive and therefore has to be reconsidered. Li also believes that only a larger mining transaction fee will maintain the balance. “By increasing block size, and transaction numbers, the fees will gradually replace the block reward, providing enough incentive for the miners to defend the bitcoin hashrate. This is the fundamental way to achieve healthy development of the whole ecosystem.”
The problem comes from the fact that the term decentralization has been overloaded to mean so many different things. From topological point of view the old graphic from Paul Baran (1964) (inset right) may seem to provide a good enough definition but only from the perspective of a network topology which is certainly not the common usage of the term today. More recently some folks have 
