They do not need to know what generates there electricity but...
- when what generates the power changes the landscape they can see, many people get upset, however irrationally
- many people are emotionally attached to lifestyle objects that use fossil fuels, i.e. cars, boats, planes, etc
- even where there are good options, most people are not willing to spend one extra penny
- even when there are options that cost less (i.e. bicycles, walking) humans spend a lot of their energy thinking about status and struggle to voluntarily choose things that they fear might result in a loss of status
- even if you solve all that, collective action problems are a named thing for a reason - they are hard and don't necessarily have obvious answers.
My point is not that everything is hopeless, but that OP who said "Have we ever as a species successfully changed our behavior on a scale..." has a point that we will have to grapple with if we want to actually change stuff. Wishing human nature away doesn't actually solve anything.
Perhaps more importantly than any of those, often people react out of fear of what they think other people will think.
Maybe everyone bitches about gas prices, but we would all get over it pretty fast if politicians just pulled the band-aid off. Instead they use it as an opportunity to pull down any crab that tries to save us from the bucket.