I'm going out on a limb and say that people are more worried about the quality of their own life than the quality of other people's life. Even if I was confident that the entire globe would impoverish themselves with me, I would still not want to be impoverished.

Besides, we don't have to scupper our quality of life. Nuclear remains on the table, for example. And it turns out thumb-twiddling for long enough has made wind & solar competitive and they're getting better. The biggest win would be cutting down population sizes and that seems to be happening naturally because it enables people to live more comfortable lives.