"Perhaps being an 'important' well-known city counts against being displayed..."
Then why are London, Paris, Mumbai, Shanghai, Tokyo, Chicago, Los Angeles, and San Francisco on the same map that New York isn't on?
Then why are London, Paris, Mumbai, Shanghai, Tokyo, Chicago, Los Angeles, and San Francisco on the same map that New York isn't on?
I wasn't implying a simplistic 'everyone knows where X is, don't show it' system - just that being well known could counter-intuitively reduce the need to show a label at some zoom levels.