Confusion regarding Transistors
Yes any real transistor does have some leakage.  Usually a resistance Ro is added in the model between the collector and emitter to account for leakage.

The equation Ic = alpha * Ie is only an approximation based on a simplified model of a transistor.  

It is no more faulty than say Newtons laws of motion, even though we know that they become inaccurate at relativistic speeds.  In the same way the equation in your book gets very close to the real answer most of the time.

Most text books start with the simplified model, and then gradually build up their model of a transistor adding additional parts to more closely approximate the real behavior.  Starting with the full model would probably hinder understanding for most people.