As we've already established, they can't upgrade the network unilaterally. But beyond that, yes. I will state it clearly and with emphasis because it's empirically true:
Any developer can create any code they want. No one can stop that in an open-source source environment.
You might take issue with that statement, but can you provide any evidence to the contrary?
Further, I feel it's one of the most vitally important features of crypto and I'm baffled as to why anyone would want the opposite.
i guess you forgot the other implementations that got treated as opposition and told to fork off.. oh wait it was you telling them to fork off. because you wanted core to be the sole brand of reference client.
and no dont try refering to very old mindset before your switcheroo..
i used to respect you in the days of 2015 and before.. but you have switched over to sound more like a centraliser and altnet fan in recent years
Apologies, but I didn't ask about my mindset or what I've said. I asked you to provide evidence to the contrary. Do you have any? I'd love to see it. If not, kindly concede the point. You cannot prevent devs coding what they want. There isn't a way to do that unless you are suggesting we make Bitcoin closed-source and put you in charge of the code repository. Is that what you are proposing?