The Supreme Court does in fact legislate from the bench. Thomas Jefferson never intended for the Supreme Court to have the power of judicial review. Chief Justice Marshall (Jefferson's cousin) just took it. The Supreme Court rarely used judicial review at first.

The Taney decision in the Dred Scott case helped to send the United States on a path to war. This should have reduced the court's power for years to come if not forever.

Unfortunately, by regulating the Judicial Branch the least, it also left it with the most leeway to make up what it's own role is. Today, we just take it for granted that the Supreme Court gets to decide whether or not it likes virtually any law past by Congress. That was never intended by the Founders.