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.
You’re making a good point. This is one of the reasons why flood and fire insurance is skyrocketing. Our historical models are no longer able to accurately predict future risk.