These "degrowth" strategies mean tremendous suffering. People have to die to make degrowth possible. Those who stick around have to suffer of curable medical complications. They have to live hard lives without the comforts of modern life.
Why do we need to descend? It's not strictly necessary: the "environment" has enough fissionable material for nearly limitless electrical power. The "environment" has enough raw material to increase the amount of computation on our planet by many orders of magnitude. And that's if we stay here on Earth -- if you want to think on "indefinitely" timescales, Earth's constraints may not apply.
It's profoundly cynical. I don't actually understand it. All of this technology, this art, this incredible organization that the modern world provides, and think "we need to turn back, tail between our legs, and give up."