I also question everyone’s ability to discern what they hear - and even sometimes whether they DO hear - what is happening in heart and lungs. It could be attributed to a sub-par stethoscope, lack of exposure/training to real-live problem sounds, and/or even impaired hearing.
Today I have my migraine. Years ago, I had a migraine during a physical and my MD questioned whether, because I get migraines, I had a murmur. He could not hear one, so he scheduled me for an echocardiogram. So I went. The tech couldn’t hear a murmur either, but she did have me do something similar to a valsalva maneuver, which actually DID trigger a murmur that is repeatable. I could feel it, she could hear it, and it showed up on the echo.... though I also question the validity of the link between the migraine and the murmur - which may suggest something chronic or even congenital or comorbid vs. a link between the maneuver and a normal heart’s reaction....
So he had apparently read some studies. But no other MD/NP has ever validated that I have one, or the correlation, etc.
So I would add lack of knowledge to the list of reasons why perhaps the auscultation is relied upon less than we think.
That said, every nurse I know and work with very much knows the value of one stethoscope brand over another and holds his/her scope close at hand.... and the doctors get to know who among us is accurate with not only hearing something that is actually there but also when to ask for what follow up. And I have been privileged to work with both knowledgeable doctors and nurses who, when something less common is heard, will invite the less-exposed nurses to come listen along.