The medical industry already profits greatly from medical testing. Testing earns the industry lots of money; then, patients with positive results receive follow-up treatments, which nets the industry even more money.
Everyone screens for cancer now. Breast cancer. Colorectal cancer. Prostate cancer. The list goes on. (I'm even a cancer survivor myself.) And yet, to this day, studies question whether more testing results in longer life spans. Generally, it does not. Meanwhile, all the testing and treatments and post-surgery therapies reduces one's quality of life, especially the older one gets.
The cited article says it best: "How could it be that many cancer screenings don’t have an impact on overall lifespan? While screenings prevent some deaths from cancer, they don’t prevent all...At the same time, cancer screenings have associated harms such as false positive results, overdiagnosis, and overtreatment (not to mention the financial cost of all these cascade events). It could be that the benefits of screening that some people receive get washed out by the harms that others experience when looking at screening on a population level."
We are already pricing ourselves out of paradise when it comes to medical care, and full-body MRIs are only going to make it worse.