Health resources are finite and colon cancer is extremely rare among young people who do not have family histories of cancer or some existing bowel problems. Norway starts colorectal testing at 55 for people without specific indicators.
Does a check cost more for young people than old? "finite resource" seems to be an issue of public health funding; private health scales to fit the market (by producing more doctors, say) - hence it's not a zero sum if people start spending more on healthcare overall.
Basic colorectal cancer screenings cost around $100, but like all health care there is considerable variance in what people pay. You are implying that we should test all people for all possible problems which is simply not practical and probably not even possible. Testing is instead based on health condition and history.
