i don't buy it. my gut feeling is that loss in number of donors due to incentive to sell will be completely offset by lowering the barrier to giving your blood. companies fighting for customers and public image will start charity programs where some % of sold blood will be donated. there are just many more ways in which blood would be donated into the system with open market than with the closed one.

It is not immoral to sell one's own blood, so long as one is not left unable to fulfill other moral obligations.

The moral bit is choosing between 2 competing blood donations service - one that is run publicly to save life, the other to extend the life of healthy individual. I make the assumption that the remuneration of the second one will be most likely way bigger than in the first case. The only reason people would chose to donate to the first one is morality which is unfair.

The morality of the remuneration is orthogonal. I assumed we were talking about countries where it is moral and legal to remunerate blood donation. I don't think that countries that today do not allow remuneration (for any reason) would allow it for this new use case.

You can still use blood from a private company for the treatments you would use "public" blood for.

struggling to find blood because almost nobody wants to give it for free. pay people for their time and donation. thats what markets are for.