How is this an interesting argument? Of course we don't have things before we build them. That's true of nuclear power plants, too. We can likely build out storage faster than NPPs, with more aggressive cost decline with cumulative production.
First, this is yet to be determined. Even assuming it is true, which I'm not sure it is, The problem is not limited to storage - you also need massive transmission system upgrades that will cost on the same order of magnitude as an Apollo program. I think in the long term it should certainly be done, but pretending that the cost of solar and wind power is the cost of solar panels, or even the cost of solar panels + storage is not comparing apples to apples.
With distributed electricity generation e.g. microgrids, the need for big, centralized storage decreases, as does the need for large-scale transmission.
By the time fusion generators exist in a practical form (at least 20 years from now), we won't need them.