I think this is mostly 'theory' at this point and not likely to ever happen. Though with all things considered, I wonder what would happen if someone got clever enough to use a proxy that has IPV6, and therefore disseminates their single address into a litany of legitimate addresses. With a handful of those, it seems like we again enter the area of 'theoretically impossible' to track, unless you're uncle sam.
I agree entirely with what you are saying, and have always lobbied for more logical solutions rather than brute force 'whack a mole'. Albeit nobody seems to want to hear that. Resource delegation alone, I think, would solve everybody's problems.