The key use for grids that can't be replaced is industrial use. Some companies need very-high quality power, in terms of frequency stability or downtime. Other

The key use for grids that can't be replaced is industrial use. Some companies need very-high quality power, in terms of frequency stability or downtime. Other companies require high volumes. For these users, it's much easier to buy service than to start a dedicated service within the company responsible for, essentially, setting up their own grid. Once you have that, connecting nearby homes cheaply is easy, and it's really a rich person's pastime to build an off-grid alternative with equivalent quality if you can get connected.