What do you call the group of developers who control write access and pull request approvals for the Bitcoin Core GitHub repository? You can't just apply to become one of these devs; they're grandfathered in from the early days. And they're the sole group who effectively have the final say on what features make it into the network protocol.
To me, that sounds like a centralized team employing centralized decision making.
The Bitcoin network is steered by these developers, but as we saw with the User Acitvated Soft Fork (UASF) of 2016, the users ultimately decide what Bitcoin is.
The vast number of users, or at least, those who run their own node, choose to run a forked version of the client software that activated a contentious upgrade (the upgrade was Segregated Witness).
Only after the fact, this code was merged into the Core branch.
The difference is that nobody has to actually accept updates that the core team make - and this has happened a few times, resulting in forks, although those cases were for things the core team refused to do - how can you “fork” a security? What is the common enterprise when forking a PoW chain?
Exactly the same way you fork a non-security. Security is a legal designation, not a description of how a particular asset is implemented (in a forkable structure like a blockchain).
> What is the common enterprise when forking a PoW chain?
The developers/promoters of the fork, potentially.
To me, that sounds like a centralized team employing centralized decision making.