It is the miners that create new blocks, that is what counts, nodes simply choose whether to follow the miners or not. Nodes can be spoofed, proof of work can not, this is why it works.
So in other words miners make the ultimate decision? If this is the case, then Bitcoin Unlimited is even worse than I initially thought. Otherwise, elaborate what you mean exactly (since everyone can vote via software and miners create blocks).
this is how really works something that known can undrestand.
https://www.youtube.com/watch?v=AikLs1P4_PAevery simple person in bitcoin ecosystem is very important. Many say that developers or miners has the power for changes that is not true. In ecosystem like bitcoin everyone must agree for a change and that is the real power of bitcoin because none can control it.
Nice video, finally someone has clearly put this topic on table: If a negotiation failed, then who had the most power will decide. He did not include the exchanges, and also he did not follow the route and dig further into the failed negotiation scenario. Saying everyone have the same power is definitely wrong
Let's analyze each actor's ability to attack another fork and defense against such attack
1. Developers
IMO, developers' can attack a forked chain use spams and special transactions, they can not do too much on a fork's code base that is not in their control. They can defend against a technical attack by committing new rules to deal with spams and false transactions. It is just like virus and anti-virus, a never ending fight but seldom affect the major functionality of a coin
Attack: 2
Defense: 10
2. Miners
Miners hold hash power, a weak chain with less hash power will be easily 51% attacked by the stronger hash power
However, a 51% attack does not affect the bitcoins in cold storage, it will just disturb the transactions in networks, and while those power are used on attacking, the attacking chain will become weaker, so this kind of fight might not be so effective to totally disable another chain
Attack: 5
Defense: 5
3. Exchanges
Exchanges are important, because they can affect the exchange rate to a degree. To be honest, most of the bitcoin's early success is ensured by MTGOX, it had the power to stablize and raise the exchange rate of bitcoin thus quickly gathered lots of fans
If majority of exchanges do not upgrade to the forked version, then that version will never gain any user support (buying expensive ASICs to mine some coin that has nowhere to sell for fiat money?). If only a few exchanges upgraded to a specific version, then the low liquidity there combined with the dump of pre-fork coins from other chains will make its exchange rate quickly drop to alt-coin level
In principle, an exchange can either create bitcoin or fiat money out of thin air, and even stop large withdraw to slowdown the market reaction, thus have certain ability to manipulate the exchange rate against a sell off short term wise. I'm not sure if an exchange will provide the trading for another forked coin, since that gives them chance to crash the exchange rate of that coin, maybe they will do that to show that forked coin is destined to fail
Attack: 10
Defense: 10
4. Investors
Investors are those who hold lots of bitcoins either through mining or through purchasing. Because over 90% of the coins are in the hands of investors, they have the biggest influence of the ecosystem. By dumping their pre-fork coins on the chain that they don't like, they will immediately create a sell pressure hundreds of times larger than average day, thus crash that coin's exchange rate to 0 in a very short time
However, when facing large amount of sell-off from opponents, unless they are super rich in fiat money, they can not defense a sell-off that is hundreds of time larger than normal, so their ability to defense against such attack is limited
You can imagine, if you are an investor holding 7 billion dollars fiat to make sure all the dumps from opponent's fork will be absorbed, the chain that you support will go mainstream. In fact you don't need that much at all, 3 billion is enough, but I guess none of the bitcoiners here have that much capital
Attack: 100
Defense: 5
5. Merchants and payment processors
Since merchant adoption and payment function require world wide transaction, they have to passively follow the strongest chain, they will not use a chain that has lower exchange rate or without super majority, and they won't support fork
Attack: 0
Defense: 0
Many early adopters are both developers, miners and investors, this makes the whole picture very complicated. But anyway, when a negotiation failed, it is not likely we will have a fork, since the power of an exchange rate attack is so huge and the defense is almost none, it is a mutually assured destruction, heavily hurt both chains and the bitcoin game is over
