For the other point, personally I don’t really buy the argument of “it’s better not to know you have cancer X, because it might end up being low impact.” If we had excellent regular screening, yes detection of low impact cancers would become a lot more common, but I think people’s perception of them would change too. If it became a common thing for cancers to be detected, but the detection could reliably say “this is likely low impact, we should just keep an eye on it but not treat it”, this would be a lot less scary. It would become normalized IMO. Cancer diagnoses are partly so scary right now because we’re often mostly catching cancers that have progressed and are causing symptoms, so the public perception is rightly “cancer diagnosis = very scary.”