Why Bitcoin Dominates¶
Why Bitcoin Dominates is a 2019 research paper demonstrating through Metcalfe's Law that a single cryptocurrency network maximizes value, and that fragmentation through hard forks and altcoins destroys value for all participants. The paper establishes the "Rule of Two" -- the percent change in network value is approximately twice the percent change in users -- and provides empirical evidence that network size, not transaction volume, is the dominant driver of cryptocurrency price.
The Rule of Two¶
From the first and second order approximations of Metcalfe's Law, a simple rule emerges: the percent change in value is approximately twice the percent change in users. This was validated empirically across four cryptocurrencies -- Bitcoin, Litecoin, Ripple, and Ethereum -- using monthly data. In all four cases, price sensitivity to changes in users centered around 2x, confirming Metcalfe's Law and establishing that the relationship between users and value is not one-for-one but multiplicative.
This asymmetry has profound consequences. A 10% loss of network users does not produce a 10% decline in value but approximately a 20% decline. Conversely, a 10% gain in users produces approximately a 20% gain in value. This multiplier effect explains both the explosive growth of dominant networks and the rapid collapse of declining ones.
Network Size Dominates Transactions¶
The paper examined whether network size (number of users) or transaction volume drives price. Regression analysis across four cryptocurrencies found that network size effects dominate transaction effects in at least three of four cases. In Bitcoin, the coefficient for user growth was statistically significant while the transaction growth coefficient was not.
This finding is counterintuitive but has a powerful analogy. A large rail system connecting hundreds of cities has economic value even if no trains are currently running, because the infrastructure is available for use. Similarly, even an unused network has potential economic energy. In online auctions, the exchange of price information (bids and asks) has value even when no transaction occurs. Bitcoin's value derives primarily from how many people participate in the network, not from how many transactions they conduct.
A Single Network Maximizes Value¶
The paper's central thesis follows directly from Metcalfe's Law. Given N total users distributed between two competing currencies A and B, the combined Metcalfe value of both networks is always less than the Metcalfe value of a single unified network containing all N users -- unless 100% of users adopt one currency. Any allocation other than complete concentration in a single network is suboptimal for all participants.
This is not an opinion but a mathematical tautology. If the community of coinholders fails to agree on which coin to adopt, the result is a reduction in value across all assets for all users. Extended to three or more competing coins, the result is the same: a single network maximizes value.
The Bitcoin Cash Hard Fork¶
The paper used the August 2017 Bitcoin Cash (BCH) hard fork as a case study. BCH split from Bitcoin over a disagreement about block size -- proponents of Bitcoin as a store of value versus proponents of Bitcoin as a medium of exchange. At the fork, anyone owning Bitcoin also received an equal number of Bitcoin Cash units.
The consequences were material. From the hard fork through early 2018, Bitcoin's daily transaction count fell from approximately 500,000 to 131,000 -- a 74% decline. Bitcoin's price subsequently fell from approximately $19,000 to $3,400 -- an 82% decline. These proportions are consistent with what Metcalfe's Law predicts.
The paper estimated that at one point, Bitcoin's market capitalization was suppressed by as much as $100 billion as a direct result of the BCH hard fork. The 2017 price spike obscured the underlying damage because some of the elevated transaction activity consisted of users migrating from Bitcoin to Bitcoin Cash, which traders using transaction-based valuation models would have mistakenly interpreted as growing demand.
Schelling Points and First Movers¶
Users prefer one currency. While governments may force the use of multiple currencies for international trade, no one would voluntarily manage 2,000 currencies in daily life. Currency is, by definition, a Schelling point -- a solution that strangers independently gravitate toward because of its natural convenience.
Historical precedent shows that technologies which gain an early lead tend to become locked in as the winner. Railroad track gauges consolidated from multiple widths to a standard gauge. Alternating current prevailed over direct current. VHS eliminated Betamax. Microsoft Windows dominates Apple MacOS by a factor of 4-to-1 despite Apple's longer history and loyal user base. Bitcoin, as the first cryptocurrency, enjoys first-mover advantages that Metcalfe's Law amplifies through the network effect multiplier.
Capital Flows Are Misleading¶
Traditional "money flow" analysis from equity markets incorrectly estimates the impact of capital movements between network assets. The asymmetric nature of network effects means that a relatively small capital flow can produce outsized changes in network value.
For example, a $125 million position liquidated from a small coin and reinvested in a dominant coin could cause a nearly $3 billion increase in the dominant coin's price, even though the capital flow represents only 0.1% of the dominant coin's market capitalization. It is the number of users moving between networks, not the dollar amount, that determines the impact on value. This dynamic also explains cryptocurrency's high volatility -- small movements of users between networks produce amplified price effects.
The Federal Reserve's Observation¶
The Federal Reserve Bank of St. Louis noted the economic dynamic using an analogy of Hamilton ($10) and Lincoln ($5) bills. If the supply of Lincoln bills increases while Hamilton bills remain fixed, the price level rises and the purchasing power of both denominations declines. The same applies to altcoins: an ever-expanding supply of alternative coins depresses the price of Bitcoin relative to where it would otherwise be, even though Bitcoin's own supply is fixed.