If one can offset your electricity bill by more the cost of the install and come out financially ahead then that is compelling to the individual, I doubt many people are knowingly eating a loss and stumping thousands upfront solely because they think they are helping the environment
Well, solar salesmen can be pretty slimy, hiding costs left and right. That said, the monopoly utility grids have a chokehold on power, and escaping that monopoly is often worth the 2-5x premium you are going to have to pay vs a utility scale project.
Plus, when people compare the cost of home solar vs utility solar, they often ignore all of the infrastructure (especially last mile infrastructure) that's needed to get the power from the utility scale solar farm to someone's house.
If you live somewhere with expensive electricity and decent sun (California, New Mexico, Arizona, Florida, the Carolinas, etc) it's usually worthwhile to put solar on your home. It's less effective than if someone competent were to spend the same money improving the grid, but in this day and age that's a lot to ask.
At least here in the UK financial literacy is so low that I think lots of people are doing exactly that.
I think most people installing solar are doing it in the hopes of improving their property value while possibly buffering their total dependence on the grid, with environmental virtue as a secondary benefit.