Evolution can't be stagnation. What you understand as decentralization and you think it's okay for bitcoin, in reality, it is stagnation.
I don't say it is OK for bitcoin. I say that a crypto currency is designed normally such that there is a decentralized consensus mechanism. If that mechanism is truly decentralized, then it LOCKS IN the protocol forever.
This has the advantage that there CANNOT be leadership, and that people using it KNOW that this protocol is going to remain forever what it is. That is a good thing for a monetary belief, that even a single individual is guaranteed that the rules apply for ever.
This is exactly where the split ETC/ETH happened over. It was "all against one" with the DAO happening. In a truly decentralized system, that single individual has the guarantee that the rules will apply strictly, and forever.
In a system with leadership, it will at best be a democracy, that is, where the majority imposes its will on the minority. As the majority can be manipulated (there are more idiots than smart people out there), this gives a strong lever arm for "leadership" to manipulate majority. Individuals or minorities have no guarantees of the application of the rules. The system can be modified in order to harm their advantages. That is exactly what ETH did: but we saw that there was a split. The DAO hacker having applied strictly the rules would have been guaranteed to have his advantage in a fully decentralized system. Because there was "leadership", he couldn't. But at least, the system broke into two pieces over that.
So the idea of decentralized consensus, which, in a crowd of non-colluding antagonists, can NEVER come to an agreement over change, is that the rules are graved in stone for ever. That should help the monetary belief: no "leader" is ever going to change the rules to his hand, or even, to the hand of a very large majority. The rules are what they are.
If a better system of rules comes out, then the idea is simply that people LEAVE the older system and take up the new one. There's no reason to IMPROVE an existing system. Let it die. Because in order to improve it, you have to change it, and then, the rules are not graved in stone any more. In that case, *anything goes*. We already have such systems: fiat systems.
What you just said, evolution, survival of the fittest, doesn't apply.
You don't like your wife anymore ? You either do this: leave, or divorce her. If you struggle for 50 years you may end up killing one another.
Indeed. But don't try to change your wife. She is what she is. If you prefer another one, leave the old one and go for the new one. But don't have "leadership" to modify her.