You can replace a rule and still hold most of the hashpower. The chain just stops being Bitcoin for everyone who kept the old rules.
That is what the quote compresses: consensus here is agreement on what counts as a valid block. Nothing in it is a vote on proposals.
Nodes enforce it and miners only order it.
The segwit2x attempt in 2017 had most of the industry behind it and still died, because it needed people to run code they refused to run.
Read 'consent of the majority' as the economy validating. A headcount among builders gets you nothing if the nodes will not follow.
