The map I see is this: https://imgur.com/h74uIJB I'd say there's a pretty large land area not within 10 minutes of a subway station.
Unless what you're trying to say is "places that don't have the public transport to support high-density housing don't have high density housing" - if that's what you're saying, I agree with you!
When you resale the map by the presence of commercial space, practically every store front you could buy would be within 10 min of a subway. Transit makes a city.
