Feels like you're on a different tack here: improving your "own life" is different from solving "collective problems".
Further, setting up solar + batteries solves a non-modest individual problem, but is not by itself (i.e. reducing carbon footprint; an example mentioned in the parent's link) the solution to climate change. (yes it helps; but incentives leading to people installing solar have a much bigger impact; and the biggest incentive was maybe China building a solar panel industry, but I'm not trying to go down that tangent)
That's fair. I think I had read the parent a little differently. I was interpreting this as situations where an individual can improve their own experience of a collective problem, in a way accessible to most. But I acknowledge that's a bit different.
With the solar+battery, I was thinking of solving grid issues and energy prices, which it does do.