There are three components to Bitcoin: the developers, the nodes, and the miners. All of them play a part in maintaining the security and decentralization properties that make Bitcoin valuable.
Developers are a source of change. In Bitcoin, you can only add features, and therefore make the system more complex. So changes must be hyper-conservative or else they can destroy the system.
Nodes are a source of sustainance. They enforce the current rules of the system against each block of transactions that is mined. And they are slow to upgrade if changes are made to the code.
Miners are a source of creation. They choose transactions and spend physical watts to produce a record of transactions that every node can agree on. Physical power is necessary to make the record of transactions trustless.
I highly recommend reading The Blocksize War to understand the power dynamic among these three participants. It is the key to understanding what consensus means in Bitcoin and how power can be projected within it.