Ingress is a great way to explore the city. It takes you to parts of the city you never have been and would not have gone. I am talking about 20 blocks from where you live. The game is also a great way to meet people. And there are good practices. Strategies are possible. But this is not exactly chess.
Right now the city looks about 60% blue. Would it be possible to make it 90% blue? I think it is possible but it gets harder as the percentage goes up.
When you are dominant, your players start taking it easy. Most prefer not to get regimented. When the city is largely blue it is great for the most active green players. They have more portals to capture.
But even going from 60% blue to 75% blue would fit my definition of victory.
Another definition of victory would be if we could turn permanently green areas like the High Line, the East Village, Williamsburg, Long Island City, the UN blue for a few days in a row.
I am under no illusion we are creating anything permanent. Permanent victories are not possible. If they were, the game would not be fun. But I think it is possible to shift the ground.