I can't really common about the US, but here in the UK the quality of healthcare is shocking bad. Although we may have the opposite problem, where instead of doing unnecessary procedures to increase costs, the NHS generally tries to avoid doing anything unless you're dying.
I had some pain in my abdomen a few years back and had persistently elevated liver enzymes. My doctor told continuously told me not worry about it and would say the pain was probably because I was sitting funny and other nonsense. In their opinion I was too young to have liver problems so there was no point in doing any further tests.
Fed up, I decided to do my own research and pay for my own tests. From this I found out that I have a fairly rare generic condition which makes me highly predisposed to liver disease and NAFLD. Certainly not the end of the world, but it pissed me off a bit because the disease could have progressed had I taken their advice and simply ignored it.
Around this time I also had a family friend who was the same age as me. She went to the doctors repeatedly over the course of a year describing several symptoms she was experiencing just to be dismissed. Turns out she actually had cervical cancer, but they never ran any tests and kept telling her it was probably nothing to worry about. By the time she found out she had cancer it was stage four and she died a few weeks later. She was 28 and had two kids.
Like you I believe in listening to experts. Most experts know what they're talking about and generally give good advice, but it's important to keep in mind the conditions experts operate in. Here in the UK the NHS has neither the time or money to give you high quality healthcare. It doesn't really matter if you see the best doctor in the world, if they can't spent the time and money running the tests you need you're not going to get a good diagnosis.