alt Hacker NewsWalk into a US gastro with a hang nail and you'll walk out with a colonoscopy requisition.
They make money on the procedure, not the office hours. And they write the standards of care.
That being said, my father delayed a screening, developed colon cancer, and now no longer has a colon. Would cheaper / higher compliance tests have caught it sooner? Hard to say.
That's not entirely true. For screening procedures it's mainly the USPTF that writes the standards. They take inputs from the gastroenterology community but the process is more holistic.
https://www.uspreventiveservicestaskforce.org/uspstf/