I hate to break it to you, but most of the legal documents you pay for
are already standardized. They have been for years (or decades, depending on the area of law). You're paying for the customizations that are specific to your situation.
Obviously, standardized language has done nothing to reduce costs. The problem is supply-side: despite the glut of (new) lawyers, there are still not enough lawyers that people are willing to trust with their business.