Outside of maybe parts of Queens, the entirety of the rest of NYC has more Rangers fans than Devils and Islanders fans combined, so I'm not really sure what you're basing this on.
What I was saying is the Rangers in controlling Midtown Manhattan by extension control most of the city simply because of the way the NY media operates.
The New York metro can support 3 NHL teams mainly because of how RSN's work in the US. Dolan made sure that MSG controls ALL local hockey in NY on TV so the YES and SNY Networks couldn't hurt MSG in the winter. The Rangers, in reality, kept the Islanders afloat with the massive TV deal and then added the Sabres to keep the channel on statewide.