Why aren't more people buying homes?

Interest rates have officially reached an all time low of 3.75% for a fixed rate..Can you believe it? Why aren't more people buying homes? Home prices in most areas of the United States have dropped at least 25% from their all time high in 2007. Why aren't more people buying homes? Many economists have predicted that the housing market has bottomed or is near the bottom. This means that prices have fallen just about as far as they are going to fall, eventually beginning their rise, again. Why aren't more people buying homes?