The economics of the case are trivial (no market, no prices, so weird allocation decisions are the norm), so let's instead consider some of the moral intuitions that lead to the existence of an organization like HHS.
- Conventional ownership/exchange
For what I assume are mostly Rawlsian and Arielian reasons, folks object to spot transactions for vital organs. Roth-style matching algorithms seem to strike a balance between the nice thick market we'd like to see and the callous, mercenary sale of the components of life we'd like to avoid. But in the sense of plain jane alienability, we're pretty far from owning our own organs. This leaves open the extremely relevant question of who does? If it's some nebulous "society", or even "medical science", we're still left with a concrete puzzle of just who it is will make final allocation decisions. Is vesting a DC appointee or an elected official this responsibility a priori superior to the natural arrangement where my guts and lights are my own?
Tissue rejection might be a reason to regret a transplant, but it's more likely that families will regret having to queue for organs, particularly when viable organs are available. One of the troubles here is that unlike markets for toilet paper (where you can buy as little as half a dozen squares in some places in the world), the unit under sale is more or less fixed. If the price of a kidney is $10,000, a patient can't just say, "well, I've only got two grand, so give me a fifth of a kidney." Renal systems don't work that way. I wonder if there might be something to Paine's aphorism here: "what we obtain too cheap we esteem too lightly" when we consider high-income patients. I apocryphally recall conversations with friends who claim that markets in organs would subsidize intemperate consumption by rich folks. Why bother taking care of yourself when you can just buy a new liver when your old one wears out? To the extent that this might be empirically true, it offends any reasonable sense of fairness.
None that I can think of.
Institutional coercion is what replaces market allocation, so there's that, I suppose. Is this morally preferable? Consequentially preferable?
- BATNA disparity
We tend to dislike debt issued under conditions of duress. Duress from crappy BATNA means that lenders can don a usurer's cap and pile on punitive interest rates. Or so it seems from third parties' perspective. Never mind I guess that organ transplants imply a somewhat stronger default risk. At any rate, it's a matter of perception: people on transplant waiting lists are desperate in an absolute sense and disparate in a relative sense. Voters and medical elites alike can adopt clinical detachment and prescribe a suite of organizational treatments. Who better to be an object of paternalism than the sick? And who better to be the paternalist than... a beltway bureaucrat in a nation of over 300 million people? Right?
I have a hunch that the ACA is going to turn out to be a hideous chimera that eats itself and within a decade or two we'll have EU-style single payer here in the US. Ask the Ollie Williamson question: is the ACA a crowbar to pry out a class of entrenched interests? Is it nothing more than a flurry-sheaf meant to overcome a transitional gains trap?