Misunderstanding efficiencies, capacities and costs lead to lobbying for subsidies on technologies.
This article point says at some point during the day, either:
1. you need high capacity & efficiency grid storage (ie hydroelectric storage)
or
2. someone engineers a grid scale batteries that have never been deployed before that are 2x more capacity than current installs and with the same efficiencies - and they deploy them in tandem with the current solar installs.
While it is _possible_, there are a lot of other people competing for energy markets... it is not at all indicated by the article that market forces will be focusing 100% on solar.
Seems like a good thing to me.