(Part of the point of having a legal fee schedule is, I suppose, to put a damper on the prices of legal help, because, like in medicine, the demand is otherwise extremely inelastic: when you need it, you really need it. That does not appear to work. I wonder if there is an approach that would work.)
Secondly, there is a morality clause with regards to attorney fees, so usurious rates like some US attorneys charge are harder to achieve.
This doesn't mean German attorneys are cheap. It's just not quite as out of control as the US legal system. (Though attorney's professional bodies are obviously lobbying to make it easier to charge more)
The legal fee schedule does put a damper on attorney work, and more importantly, makes it somewhat easier to predict costs should you need an attorney. If it's enough of a damper is open to interpretation. I
Of course, if there's one thing that lawyers are less likely to do than cap the earnings of their profession, it's to devalue it entirely.
You could also increase supply by reducing the level of qualification needed to become a lawyer. Increased competition would drive prices down. That too is highly unlikely.