You’re correct that the system is statistical, and it’s planned accordingly. However, we cannot omit the fact that it’s the running turbine that responds faster to the unpredictable nature of the grid. The backbone of the grid, aka the baseline plants, are extremely responsive to unpredictable nature of the grid at a greater scale, with enough amount of safety margins to bring into service under unusual circumstances. I really don’t see, at least what we have in hand rn, that happening with solar or wind. Without strong baseline you’d experience supply demand imbalance, in engineering terms frequency decay, voltage collapse.