1. Nobody takes "spheres of influence" seriously in modern day. It's a 19th century simplification that divides countries into empires and colonies. It doesn't really describe the complexity of modern day international relations where even very small countries like Iceland can have disproportional impact.

2. China is building a military base in Cuba, and yet you are probably not even aware of that, because again, the world is a little bit more complex than what you've become to believe and officials operate with more than just a phone line to bomber command.