It's a nice fantasy, but it's simply not the case in my experience. The details are deferred because you want to be able to adapt some things faster than you ca

It's a nice fantasy, but it's simply not the case in my experience. The details are deferred because you want to be able to adapt some things faster than you can change a law and you want it done with a comment period by subject matter experts, rather than by legislators. In general, however, those agencies are slow moving (requires comment period, must decide given bounds, funding limited, etc) and pretty narrowly handcuffed / acting within the statute. Recently even those narrow powers have been rejected by the courts (see admin law judges, CFPB single director, etc).