Nobody knew your scenario before you explained it in detail.

I thought that “altruistic organ donor” was a well understood concept, I was wrong.

It is simply not happening.

You’re factually wrong on that aspect.

I don’t think anyone just randomly donates a kidney, like you would give blood

You would be wrong about that, in 2021 more than 450 people in the US anonymously donated a kidney to a non-familiy member (source). This is the scenario I’m asking about. One of the arguments given is that just as we allow monetary donations to specific groups of people, why not organs.

The question here is about a voluntary kidney donation from a living patient.

Are you sure Germany doesn’t have an altruistic kidney donation program?

This document from 2016 agrees with this assertion (bottom of second page).

It seems such a waste, this podcast makes it sound an amazing idea https://freakonomics.com/podcast/make-me-a-match-update/