Sure, but that can happen with too much efficiency, too. See, for example, supply chains during COVID. We had a very good handle on how much (for example) toilet paper we needed in normal times, and produced almost exactly that much.
Having some extra power generation capacity means you're not freezing to death in a cold snap or frying all the elderly in a heat wave.
It's OK to be inefficient sometimes.
Everyone feels this way until they personally have to pay more money for something.
Sure, but that can happen with too much efficiency, too. See, for example, supply chains during COVID. We had a very good handle on how much (for example) toilet paper we needed in normal times, and produced almost exactly that much.
Having some extra power generation capacity means you're not freezing to death in a cold snap or frying all the elderly in a heat wave.