I'll start this post by revealing my sources. One of them ran the theatre department at Columbia in the late sixties. Another source is a recognized expert on modal jazz, who lived in New York in the 80s. The last source is a close friend and advisor from my former anthropology department, who is a native New Yorker.
Independently, all three of them speak of the importance of the conservative, property-owning revolt in Manhattan to the social unrest of the sixties. The landmark victory of that movement was the destruction of rent control, which allowed gentrification to spread like wildfire. Before this, an artist could share a room in Manhattan for ridiculously cheap. This opinion is widely shared, and it can even be found in the social science literature that is taught to undergraduates around teh world. --The New York City that most of us around here have grown up with, was largely already gentrified, and the gentrifiers were in the business of branding the city. We still get on a knee for that city in the same groveling way, even though it has transformed into a place where art is largely curated and shown, but not produced in anything like a similar fashion to the way it was when New York was cemented in our minds as the ur-city.
The Hip Hop movement of the late-70s and 80s was a transcontinental phenomenon, and New York was a main (not the sole) axis. A lot of the conditions for this movement were created by redevelopment projects (i.e. a later wave of gentrification and police control over poorer areas) which were destroying communities. Of course, that only meant people were just moving elsewhere within New York and having different social/cultural encounters. This is also the time when the IMF and World Bank were destroying an island a day in the Caribbean, and many of the refuges ended up moving to New York in that tumultuous time. In short, Queens and other poorer boroughs saw lots of external and internal migration. This wasn't a "New York" thing.... the only reason to say that is to point to a place on an arbitrarily defined political map.
Latino and Black communities in New York boroughs were absolutely well connected to Oakland and Los Angeles after WWII. In terms of arts and culture trends, while there continue to be differences and distinctions everywhere, those cities have been densely linked and informing one another in a tight loop. To absolutely exclude LA from the jazz, punk, skater culture, etc. is straight up and down laughable.