Who controls the blockchain ?

Blockchain networks tend to support principles, like open access and permissionless use, that should be familiar to proponents of the early internet. To protect this vision from political pressure and regulatory interference, blockchain networks rely on a decentralized infrastructure that can’t be controlled by any one person or group. Unlike political regulation, blockchain governance is not emergent from the community. Rather, it is ex ante, encoded in the protocols and processes as an integral part of the original network architecture. To be a part of a community supporting a blockchain is to accept the rules of the network as they were originally established.

In a blockchain transaction, you don’t have to trust your counterpart to perform their obligations or properly record transactional data, since these processes are standardized and automated, but you do have to trust that the code and the network will function as you expect. And just how immutable are blockchain ledger entries if the network becomes politicized? As it turns out, not very.

Source: https://hbr.org/2017/04/who-controls-the-blockchain