These are in the news again today. Dramatic results, yet they are not new, nor in common use. Why? This article suggests: 1. No obvious way to make a lot of m

These are in the news again today. Dramatic results, yet they are not new, nor in common use. Why? This article suggests: 1. No obvious way to make a lot of money off them. 2. The best is the enemy of the good. Hard to determine optimal metrics and doses. 3. Inertia against change in a risk-averse profession