Before we do a knee-jerk and attack Doctors.....
Having family in the medical profession, I can tell you this is happening largely because Doctors are being told what to charge, even if they lose money on it. An example is the cost of a recent MRI that I had cost $1650. My provider paid $890, leaving $760, of which the Doctor can only charge me $350 as dictated by the provider and the powers that be. The Doctors loss is $450. My family is in Dentistry and they lose money on certain procedures in the same way, but in a smaller scale. So why continue procedures that you lose money on? That is also why cash is still king at the Doctors office.
The doctor is not "losing" $450. MRIs are vastly overpriced on a routine basis. If you had to pay the whole $1650 instead of $350 you would shop around. Then you would discover that you could get the same MRI for a fraction of the cost.
Which is another reason we are being pushed to a socialized system. We are half way there. These tests are often a make or break thing for the practice.