They're right, though. Doing both is dumb. The alternative to renewables + storage is nuclear + storage, with the nuclear + storage having the advantage of the storage capacity needed being more predictable and a bit smaller, but with the massive disadvantage of the nuclear being extremely expensive and slow to build. But building enough nuclear plants to do what you're proposing, and then turning them off most of the time to get energy from the renewable plants you're also building, and only drawing from them unpredictably, is objectively the worst option.