What kind of storage? I wouldn’t bank on chemical storage technologies, at least if we want the type of reliable electrical grid that’s allowed us to develop as advanced industrial nations. Generally, reducing storage cost runs into the type of physical limits that software and silicon haven’t really encountered (yet). I wouldn’t bet against human ingenuity in the long term, but it’s not clear how the storage problem can be solved in the short-to-medium term.
In other words, you have chosen to assume. Storage cost is plummeting for the same reasons wind and solar costs did and still are: manufacturing scale.
