Jim Kasson has a nice study of an Adobe Standard DCP profile for a Sony FF camera, and at the end he quotes Eric Chan (one the Adobe colour guys) – my conclusion from all of that is that when people design a general purpose input profile, accuracy is not their highest priority. Cameras are not meant to be used as spectrophotometers.
And even when camera makers or Adobe design their"neutral" profiles, they are never 100% neutral (accurate) either.