As you’ve identified, few people will opt into a lower quality of living in the name of the greater good. The solution is to find better power generation methods, rather than force people to accept a downgrade.
Well, it's not that much about acceptance, the downgrade is being forced on people right now (via drought, ocean rise, heat, fire, and other climatic events, and all this will also cause hunger, population move and wars), and it's a much worse downgrade than what people could do volontarily to mitigate the issue.