MD-PhD programs are quite collegial and share information with one another, so I have had access to data from many programs over the years. It is from this perspective that I can say that the average MCAT of entering students is practically identical for most MD-PhD programs. Please refer back to a post I made several months ago that showed the distribution of MCAT scores of my program's matriculants in recent years. You will find that this distribution is repeated at other schools, whether they be WashU, Hopkins, P&S, UCLA, Emory, Harvard, etc. Furthermore, the average scores at most schools have been stable, rising perhaps one or two points since the adoption of the current MCAT 15 years ago.
Your assertion that a particular MD-PhD program is the mother of all MCAT mongers and that it has recently changed its admissions criteria to give more weight to MCAT scores is both spurious and lacking in rigor (you used an n of 1). The fact is that MCAT scores are a minor consideration for MD-PhD programs. MCATs have little predictive value beyond USMLE Step 1 scores. They do not predict an individual's future success as a clinician or a researcher. To make high MCAT scores a critical factor in admission would be more than silly: it would be suicidal. Please give MD-PhD programs credit for having figured this out. Some of these programs have been around for more than 40 years, and they have enough experience to know the proper value of MCAT scores.
The rest of your post is accurate.