Why does the United States have over 52,000 troops stationed in Germany?

After the End of WWII all four victorious nations (USA, Britain, France and USSR) had troops in Germany to occupy the country. When the cold war began Britain and the USA kept their bases in West Germany to protect Europe from the Soviets in East Germany. After the collapse of the Soviet Union and the reunification of Germany (which included the withdrawal of all Soviet forces) most of the British forces left as well but the United States kept their Air Bases in South Germany. Those bases are usually used as logistic centers, command posts or hospitals for troops operating in that part of the world (mainly the middle east). While the US have bases directly in that area (like Irak or Afghanistan) it is probably cheaper and safer to treat wounded soldiers in Ramstein than in Bagdad or fly them around the world to the United States. After all those bases in Germany have an established supply infrastructure and there are far less suicide bombers...