Consensus can change. Blockchain are just databases. But they still run due to consensus and the consensus is made up by humans and it is humans who uphold it.

Consensus can change. Blockchain are just databases. But they still run due to consensus and the consensus is made up by humans and it is humans who uphold it. For example, humans came to a consensus that there will there will only ever be 21 million Bitcoin. However, we cannot guarantee that one day there may be more than 21. They also came to a consensus that that this shall never change. However, all that is protecting this consensus is a meme. The source code can be changed should everyone agree, especially if the future humans find that such a cap does not work. The benefits of decentralization is that the consensus is hard to change by individuals or centralized organisations... Consensus must be reached by all of the participants of the network.