Every time I see somebody make an argument about "externalities" it's never actually backed up with any fact-based analysis about the magnitude of them. It's always exclusively vibes-based, "this thing you like is too cheap, it should be prohibitively expensive to make up for the thing I just thought of"

Well, if some bureaucratic governing body provides decisions based on some opaque system, and forces these upon market participants - usually that is regarded just the opposite of market-based solutions in economics. Those decisions do have zero chance of internalizing external costs, but most likely will just add an other layer of externality and move the process even more into the field of non-market based coordination mechanisms.