This may be true, on a watt basis. It also ignores the physics of a synchronous grid. You need to produce exactly what you use at any given moment. If you fail to do that by a little bit bad things happen. If you fail by a lot, the grid fails. You need to be able to get power when you need it, not when it's convenient to your generation plant. If you want to compare solar or wind to something more dispatchable you should really be using numbers from either a pretty massive distributed overbuild or including storage or both. Otherwise it simply isn't apples to apples. I am an electrical engineer specializing in the design of control systems for renewable generation.
That's what over building is. It also requires massive investment in transmission infrastructure because your core assumption is that power in one place get get to load in another. It turns out that transmission costs many many times what the generation does
