But at that point your question isn't "what would be the payback period if I got solar" but "how much is it worth to me to have power when the grid is down". And so not surprisingly many people get solar but don't install a battery.

(Systems that provide a small amount of best-effort when-the-sun-is-shining emergency power when the grid is down seem like they should be a sweet spot here, because they can be implemented very efficiently. Unfortunately a combination of consumers not wanting it, the NEC not prioritizing it, and the shift to microinverters means that instead of adding ~$200 like it did when I got solar several years ago it's now more like $7k)