You can store energy, it's not a use it and lose it situation. EVs do this. On your second point, things that are absolutely necessary like you're refrigerator, could be on the grid but everything else isn't or it's a mix or hybrid.

Also, why is everyone only talking about what's on the market? Americans are extremely inventive, there are ways to add personal power in that could be hybrid and smart so you could control all that. You wouldn't have to make it an island but readjust your wiring to handle both. How are Europeans doing it?