It’s such an own goal to take massively distributed and resilient power generation with no inherent single point of failure and just give it one anyway.
The generation isn't naturally massively distributed and resilient, that's the thing. Assuming that the grid will always be there and stable simplifies the problem quite a bit: all the inverters have to do is sync up with it and then dump all the power they've got into the grid. If you want the solar generation to be the grid, rather than just boosting it, suddenly you have to deal with all the hairy control theory problems involved in grid operation and stability, except that you have to do it using millions of generators rather than thousands - and the behaviour of those generators is closely correlated, so you still have to deal with problems like a large proportion of generation going offline at once as well as the extra complexity of a much bigger system.
Old-fashioned spinning generators also naturally act to stablilize the grid by pulling energy out and dumping energy back in through their inertia as necessary to counteract changes due to varying demand and supply. Solar and wind don't inherently do that: if you want similar behaviour from them, that requires additional software and sensing, and obviously for home solar that would have to be done in a distributed fashion which complicates matters further. (The grid is not in fact at a single frequency and phase everywhere, and can develop all kinds of interesting and undesirable oscillations.)
Old-fashioned spinning generators also naturally act to stablilize the grid by pulling energy out and dumping energy back in through their inertia as necessary to counteract changes due to varying demand and supply. Solar and wind don't inherently do that: if you want similar behaviour from them, that requires additional software and sensing, and obviously for home solar that would have to be done in a distributed fashion which complicates matters further. (The grid is not in fact at a single frequency and phase everywhere, and can develop all kinds of interesting and undesirable oscillations.)