From the data we did get our hands on, I remember seeing price differences like $200 vs $4k for the exact same procedure. The low cost provider was usually a private practice radiologist in a small shopping mall type retail location who ran a very efficient, low overhead practice. They were terrible at marketing and ran discounts for volume from certain channels. They were only open Monday to Friday from 8am to 4pm, read times could often (but not always) be slow, they handled the least complex cases and no emergencies. Cash pay up front from patients resulting in no/minimal collections. The high cost provider was usually a large University affiliated medical center who ran a less efficient, high overhead radiology department but who also, in their defense, had to handle more complex cases as well as be open 24/7 to service one or multiple emergency departments with faster read times. Lots of fighting with insurance companies for eventual reimbursement. Lots of bad debt that went to collections and had to be written down.
If you pay University prices for a simple MRI you are effectively subsidizing the ED admit who needs a complex imaging procedure in the middle of the night. If consumers start to shop for MRIs the way they shop for airline tickets - which they probably should - one downstream effect will be to remove billions of dollars of "subsidies" from the most well-resourced radiology departments in the country. If I remember correctly the diagnostic imaging market was something like $150 billion/year in 2015, and probably even bigger now, i.e. plenty of potential fat to cut.