Sltldr: “They’re just throwing away money, planting trees in the desert for them to die.”
The Great Green Wall is a top down, big government intervention that has little to no local buy-in and isn’t sustainable without continued big government funding.
Not surprisingly, the funding has mostly dried up, and so has the land.

Not the main point at all of this article, but: “The price tag was also massive: the United Nations estimated that $33 billion would be needed to complete the Wall.” Still less than the US spent on the Iran War in less than a month.
America is always complaining about being broke but always finds the money for war.
They’re like a drug addict, always broke but somehow finding the money anyway.
Musk can cover that with some shit from his pocket. Do it and send him an invoice