> Eagerly awaiting a substantive response to this by maaku.
I am very much not maaku, but first it's obvious that Proof-of-Work has not been used to decide consensus protocol parameters (it's used for transaction ordering and establishing the consensus history). Second, Bitcoin success or failure is entirely unrelated to how the protocol wasn't designed to vote on consensus protocol parameters.
As long as the changes are non controversial then miners and nodes simply act at a rubber stamp. But it's unrealistic to think no important issues will be controversial.
If consensus changes arent up for CPU vote, then you tell me what happens if a supermajority of miners and nodes decide to run software with different consensus rule from Core? Sounds like a CPU vote too me.
Every "soft-fork" to date has used PoW to activate new consensus rules by requiring block version super-majority.
Consensus rule parameters are things like "max block size". However, there have been some proposals for extension blocks to increase block size without requiring a hard-fork (e.g. using a soft-fork mechanism).