Go to a country with just that and witness how stupidly wasteful it is to have an energy grid with regular outages. Everyone who can afford it has an expensive backup generator, batteries, etc. For industry, it's a disaster.

I live off-grid, with solar and LifePo4, but I'm not naive enough to think that would scale to an economy any time soon. And for the record, no below 99% availability should be seen as unacceptable.