https://www.humanprogress.org/dataset/southern-white-rhinoceros-2/
https://www.perc.org/wp-content/uploads/old/Saving%20African%20Rhinos%20final.pdf
I’m not well-versed enough on these matters but my amateur takeaway is that this seems to show the perfect marriage of public policy and market-based thinking. What particularly stands out is what seems like a remarkable willingness to be flexible and evolve policy over time based on what was actually happening as opposed to what the policy makers wanted to happen or thought ought to happen. That seems woefully absent in most government systems/institutions.
If I had to draw a crude analogy, rather than the state setting up a centrally controlled market, they put enough structures in place to turn a barren, crime-filled lot into a thriving flea market where various private actors could make mutually beneficial deals and the inherent competition led to improved “products” (e.g., white rhinos).
There's a really big and interesting topic in economic history here: For most of our development, property rights in most living creatures have been harder to maintain than the property rights in the same creatures' remains. The exceptions have been herd animals because herding behaviors lower the cost of protecting the animals--they're already together in one place, after all. But other animals are not, and so the most value we'd be likely to get from them would be by just hunting them.
That remained true through the age of European exploration, but the gap has since then shrunk a lot--property rights in living creatures have become secure enough that the strategies of raising them or keeping them in conservation areas can both make sense, rather than the strategy of hunting them to extinction.