For me, punk is in essence a British social movement (with music to go alongside it, but not the core content) spawned by the Brit class society's stiffling effect on British youth in the mid to late seventies. It grew from there. But, say, four kids from affluent suburbia homes in Southern California playing their guitars in buzzsaw style is as "punk" as Disneyland's depiction of the Black Forest is Germany. They play music that cites punk music influences, that is all.
I accept that the American view might be different.
If you derive you definition of punk from the music press then I can see calling it a British social movement and it is indeed dead.
The Disneyland analogy is apt, once again though it is seeing it and defining it through the eyes of the press. You may have heard of the affluent kids from So Cal because somebody has money to promote them. But again, examples of the opposite don't prove the real thing doesn't exist.
There was a huge difference between what the press reported and what was really going on in the late 70's and early 80's. The Ramones were dismissed as a joke and rarely mentioned in any media before 1979 when Rock N Roll High School came out. (at least in the US outside NYC). And I have to agree, they were not political punks, they just wanted to be famous. They did inspire the British social movement though.
The Black Flag/Minor Threat era all happened via word of mouth and posters on telephone poles. And that was a big part of the point. They didn't need the media to make them legitimate.
So you're right, we have very different definitions.