Earlier quoted context omitted.
That problem inflates the cost of solar and wind a bit, but it's not enough to save nuclear.
But... it's not about cost. It's about having energy available . If weather reports show overcast and low winds, and your grid runs on wind/solar power only, who cares about their electricity bill? There won't be any kWh available to consume.
Of course it's about cost, the cost of achieving that availability.
Oh, I see. You are somehow imagining that storage cannot exist. Please stop.