Very interesting post.

Experts in the fields use it more than novices, and get better results, so it's certainly of practical use in many settings.

To what degree should the better results be attributed to greater use of RPDM? Another possibility: (a) more experience leads to more effective use of RPDM, and (b) the more effective RPDM is, the more likely a person is to use it. This hypothesis also predicts that experts would have better results and use RPDM more--but the better results would not come simply from the increased use of RPDM. They would more properly be said to come from added experience.

Support for (a) comes from your sentence "It seems to be at its best when there is reasonable experience to draw upon."