Sports Obsessed Nation

I often wonder why US is so obsessed with sports, mainly Football, Basketball and Baseball. Everyone talks about it at work or social gatherings. I am amazed to see them being obsessed about sports which do not even have an international presence or have a negligible international presence at best. 

Everyone seems to have knowledge about these games and has an opinion about it. Even the schools would let you leave if you want to watch the "World Series" and in most cases schools would themselves leave the class early. People would cheer for their state teams would wear their T-shirts and would do tailgating (I have still not come to terms with the tailgating concept). Everyone talks about it from common man to a politician to a movie star to academicians, one and all. In a way it feels like it binds everyone but on the other hand it seems like people are just split into factions, just supporting their own state team. 

I have not seen people talk so much about sports in which US really has an international presence like Tennis, Swimming, Soccer etc or which are truly international. May be most of the sports in which US has done well in international arena are individual sports and I guess people find the team sports more interesting.

I cannot talk about other countries, but as far as India is concerned I have hardly seen people talk about any sport other than Cricket and that too only the truly international matches. But even for that, I do not think people would go to watch a game or their favorite player in extreme weather conditions with their new-born or little kids.

There are some questions that have been troubling me for quite sometime. May be I would find answers to some but for some there isn't one. Why is the baseball finals called a world series when it just involves US? Why is football called footbal when it is hardly played using the feet? Why are these sports not played in other countries? Why are there no real international matches?