Developers. Are. Not. Governors.
[...]
A hard fork resulting from a significant majority of those securing the network (that's a mix of both mining nodes and non-mining full nodes) freely choosing to run code enforcing new rules is exactly how Bitcoin was designed to work and is NOT a change in governance.
Allow me to _slightly_ disagree (although I support your conclusion - a hard fork supported by miners
& economy is perfectly legit for me).
Developers have a kind of "informal" (de facto) power not granted by the protocol, but that was probably taken into account when Bitcoin was conceived. I would describe it as
social leadership.
Miners and economic nodes - the two groups you're referring as the two main power holders - do not decide "out of thin air" what client/protocol version they run. They must choose from the available implementations. If they want to create an own implementation, there are a lot of costs for them because they would not only probably need to pay developers, but also they'd need a marketing fund to assure most Bitcoin users run compatible software.
That is only a descriptive analysis - I simply recognize that
people perceive developers as "leaders", but that should not mean that I think they
should dictate development. But they are an important power group. One of the reasons is probably that good developers are scarce, and so there is not much competition between development teams - so not every idea can get enough traction to be transformed into an implementation that works (and is essentially bug-free enough for a multi-billion dollar network like Bitcoin).