Nobody lives upstate, relatively speaking. New York State’s population is 19.5M. 8M live within NYC limits. Another 8m live on Long Island and 2M in the counties just west of NYC. So around 1.5M for all the upstate areas combined compared to 18M in the metro area.

I think you are double counting Queens and Brooklyn in that estimate of Long Island because between the Metro areas of just Buffalo and Rochester is over 2 million people not counting places like Syracuse and Albany.

Yes, New York like most States is full of dozens and dozens of counties with less than 10,000 people but they add up and while the city proper of Buffalo is like 1/10th a single Borough in population, it too has suburbs and exurbs. Even the area around Fort Drum is just over 100k people.