We don’t advocate less frequent scans, we advocate targeted scans. Because the probability of a positive result being a false positive depends heavily on the population. In a population with a high baseline frequency, the probability of a positive being false is relatively low; in a population with a low baseline frequency, the likelihood of a positive being false is relatively high.
So, you don’t mammogram every person with a breast. You mammogram people with advanced age, genetic predisposition, etc. so as to select for a population with a reasonable baseline frequency. Various professional bodies and the USPTF put a lot of effort into determining what the optimal screening population is.
Clinical decision rules are an extremely active part of medical research. Trying to figure out a reasonable predictive model to say “definitely follow up on this” or “definitely don’t” is a huge field in medicine. For instance, in patients ≥35 years old with incidental pulmonary nodules on CT imaging, we have the Fleischner Guidelines for when and which follow-up is appropriate. But it required a number of prospective external validation studies in order to properly validate it, and it’s for one super specific population: under-35 incidental pulmonary nodule on non-cancer-screening CT. So, you can imagine how much work there is to be done for the other 10,000 kinds of incidentalomas.