>Either way, we need a larger and more capable grid, so that production and demand can be balanced over larger areas.

Yup. Larger power markets benefits every kind of power: wind, solar, and nuclear. There is a lot of resistance to this though. Every state would prefer wind sites build in their own state, rather than buying power from the windier state farther away.

If you had a truly national sized grid then the power distribution between even just wind and solar is remarkably stable.