most doctors in the US actually do not know about the prices of treatments as it changes based on insurance administrator/insurer, and then what the patient pays also have huge variability based on insurance administrator/insurer.
Agree with the ethics, but if someone presents with a broken leg do you xray it (cheap) or mri (expensive)? For anything vaguely complicated the Dr is basically just eliminating likely culprits. Its preferable for everyone (that doesn't have a profit motive) if they try the cheap/quick ones first.
Even my dentist in a private practice often doesn't know "Well, we'll bill this to the insurance company, but they might not cover it all so we'll have to bill you"
In my experience, staff generally know how to code referrals for lab work and specialists so patients' insurance will cover it. But sometimes they screw up. So for example, I've been prescribed a testosterone supplement. But insurance won't cover testing for blood testosterone, level unless they use the right diagnostic code. Also for prostate-specific antigen checking. They have to code "enlarged prostate" in order to have it covered. There's another code for routine testing, but it isn't enough.
Its scummy and fraudulent, but issuing a large bill to an insurer, then getting a much smaller check back is how medical billing works here in the USA. Having your insurance pay for a trip to the ER after a car accident would be $7k for them, or $84k for your car insurance, hence why one should carry a car insurance policy with good driver/passenger injury coverage :P
Insurance should really be only high deductible plans, so the patient really looks into pricing for his general care/periodic care.