My parents pay $1,200/year for electricity, in a fairly large house. Given the expected lifetime of a power wall, that will eat all the 'savings' of living off the grid.
There's also the matter that if, say, 40% of the population disconnects itself from the grid, that doesn't mean that the cost of maintaining that infrastructure will drop by 60%. Someone will have to pay for it.
There's also the matter that if, say, 40% of the population disconnects itself from the grid, that doesn't mean that the cost of maintaining that infrastructure will drop by 60%. Someone will have to pay for it.