Technically, solar and wind are dispatchable as well, and much better than even natural gas at that. Grids were both are regulated on the sub-second scale are much more even than is otherwise possible. The thing is just that we consider that as lost energy, even though it is simply the same as running any other power plant at full power. If wind were three times cheaper than natural gas and we hence build three times as much of it, the achievable capacity factor would not look that bad.