I think the tight feedback loop for multiple scans is a good idea worth exploring, but the larger idea of building alternate systems has a problem that there's

I think the tight feedback loop for multiple scans is a good idea worth exploring, but the larger idea of building alternate systems has a problem that there's no clear path to a viable end-state. With diagnoses, collating a consistent set of data is not a requirement you can impose because of how fractured the healthcare system is. If you had great AI systems in place maybe they could be convinced to invest in these systems, but you don't and so creating them is quite difficult. Similarly, in the case of cars having their own highways and roads: how do we do this in a way that people find acceptable? If you prevent current highways from being driven on by normal cars, you cut off the majority of people from their daily commute which is a nonstarter. Making new highways in most places will also be a nonstarter for both cost and space reasons. At best you might hope that decades from now every single car has the means for self-driving in the limited environment and then one day the government turns it on, but that also feels iffy to me. Building parallel systems incrementally creates harder technical problems but allows you to side step even harder coordination problems.