In the chapter in wich we analyzed the critical points of the current monetary system we have mentioned the economic policy behind Bitcoin, completely different from that of the current system, called fiat system (see glossary), and similar to that of the Gold Standard because it is also based on scarcity, even if digital.
In the following table we can observe the main differences between the current system (fiat) and Bitcoin.
MONEY TYPE: it indicates the form in which the money is presented. In the fiat system, 10 to 20% of the money is in the form of notes or metal coins, the rest is digital. Central banks can make fractional reserves. If this reserve is limited to 10%, it means that out of 1,000 USD deposited, only 100 will be available in the form of banknotes for possible withdrawals. If we take the example of capital control in Greece in 2015, we see how this fractional reserve has manifested itself in moments of lack of liquidity in the banking system: tourists were warned in advance to bring enough cash to avoid being left without money. Bitcoin is 100% digital and no more money can be created than the software put into circulation.
SCARCITY: the issuance of currency is unlimited for the fiat system (subject to quantitative easing), while it is limited to 2.1 x 10 ^ 15 basic units for Bitcoin, further divisible downwards.
INFLATION: inflation in the fiat system is theoretically infinite but as an ideal reference it has an annual 2%. Bitcoin inflation is predictable and limited and refers to the monetary issuance rate. From 3.73% today (2019), it will drop to 1.88% starting from 2020. Inflation halves every four years and will become deflation from 2140.
DURABILITY: the durability of banknotes is limited: they can be lost, destroyed or stolen. The digital money of the fiat system is subject to hacking and seizure. In the Bitcoin system private keys can be lost, not coins. The system was created in order to be non-censurable, non-sequestrable, non-destructible.
ISSUE: fiat money is put into circulation by governments and central banks. Bitcoins are released by the software according to the rules of the network.
CONTROL TYPE: in the fiat system, control over money is centralized and political in nature, in Bitcoin it is decentralized and no one has direct control over the entry or transactions. Transaction blocks are verified by system nodes.
ADOPTION: in the fiat system the adoption is imposed by force through the law and/or military power. In Bitcoin the adoption is on a voluntary basis; no one can force you to accept bitcoins and nobody can stop you.
COUNTERFEIT: cash is subject to counterfeiting, digital fiat money is difficult to forge but is subject to third-party attacks. In Bitcoin it is practically impossible to discover a private key through third-party attacks and bitcoins cannot be counterfeited.
FUNGIBILITY: the fungibility of cash is high (except for "marked" banknotes), but is very bad in the fiat cashless system. In Bitcoin the fungibility is good on blockchain, excellent on second layer.
DIVISIBILITY: the divisibility in the fiat system is low, typically limited to two decimal places. In Bitcoin it is high, equal to eight decimal places. On second layer it is possible to use smaller digits than satoshi.
Bitcoin's economic policy has been well defined in the construction phase of the system. The fact of having set up the network in this way, even before starting with its Genesis Block, makes this economic policy its foundation. It should not be changed, otherwise the entire building will fall.
So the Bitcoin economic rules cannot be changed?
The only part of the apparently non-modifiable code is precisely that relating to Bitcoin's economic policy. When I explain Bitcoin in my country, I ask audience to imagine the Bitcoin Protocol as the Italian Constitution. The first part of our Costitution, Fundamental Rights, is not technically modifiable unless a civil war is made. In Bitcoin, "civil war" means hard fork, an IT term that indicates the bifurcation of open source code by one or more developers that makes the new version not compatible with the previous one (see What is a fork?).
So, taking up the question, no, the economic rules of Bitcoin can be modified, but only by reaching Consensus (Consensus hard fork) or by performing a hard fork without the Consensus but with the consequent creation of another chain with other rules and coins.
Risky forecast? This fork will fail.
Why? If I told you that tomorrow you can have a monetary system with more bitcoins than you can have now but that the value of the single bitcoin will drop dramatically, would you support the change to economic policy? I don't, because I don't want my purchasing power to diminish over time. My node will provide support for the only chain whose economic policy has not changed.
Let me clarify this point with an example.
Let's pretend for a moment that I have 0.1 BTC, or 10 million satoshi - which is impossible, because all my satoshis have been lost in a boat accident - and that there is a limit of 21 million bitcoins as a total supply. A modification to the Bitcoin protocol is proposed which aims to raise the limit to 21 billion. My 0.1 bitcoins will remain the same but now they would be put into circulation 1000 times more bitcoins than before. My purchasing power would inexorably go down over time. And if these 21 billion bitcoins were "coined" in the same timeframe as the current protocol, that is to say adding 3 zeros also in the amount of bitcoins released to the miners and ending in 2140, my purchasing power would be practically wiped out overnight.
My node would oppose this proposal.
How to? Simple! Avoiding to install the new software that contains the new emission rules and the new total supply.