Unfortunately wind and solar isn't homogeneously distributed around America nor the globe. The highest capacity, for both, in the US is more central US and not the coasts. This creates a lot of added complexity as those places also tend to be the lowest population density AND a large distance from said population centers.

So we can store our storage centers closer to population centers, but we can't generate it close by. We now have lots of transmission losses and opportunities for failures.

The problem with all this is that it is exceedingly complicated and most people are trying to simplify the problem. But here even including second order factors doesn't give you good approximations of the solution.