The thing is, the grid from the perspective of an average residential user is actually not that reliable. In many places in the Pacific Northwest where trees fall on power lines in winter storms the grid does not meet five nines reliability (52 minutes or less outage per year). A properly implemented whole-building off grid battery system and a few inverters running in parallel can be much more reliable than this. The grid is subject to all sorts of failure modes from trees, landslides, flooded vaults and things involving the environment, while a PV system has no moving parts (perhaps except from a ventilation fan in an inverter), and a larger set up can be run with several inverters in parallel providing AC for a building.

If you're still using above ground power lines for local distribution then that definitely would make a difference when it comes to reliability. Just like in Northern Ontario where our solar/wind homebrew solution was a lot more reliable than the local grid. Even so, in a developed country that's a choice, not a necessity.

Isn't it really cloudy in the Pacific Northwest during winter?