I think I have only had 1 power cut longer than 5 mins in the last 15 years (SE England), it's not a big problem here. (Bigger issue in Scotland/Wales/Cornwall as they get bigger storms)

The grid already allows some areas to be cut off and others continue when there is a problem or lack of generation (see ZA load shedding for an extreme example).

I think what you are asking for is for the generation to be spread out so that everywhere is almost self sufficient, but can rely on others when they are not?

It's a nice idea, but I don't think it's feasible as the economies of scale make big power plants/big offshore farms more efficient. Generation will almost always be concentrated into a small number of locations. It's also much harder to balance load/demand on a smaller grid - if your street was a grid and had to operate off grid off rooftop solar for example how would it cope when everyone turns on the oven for dinner?