Cheaper yes, but I don't think Lithium is that cheap, or ever will be. I think storage (even the expensive ones like pumped hydro) will become more useful over time to handle day/night issues. Probably even enough to handle 2-4 week variations in weather. However for seasonal weather storage is going to be too expensive compared to just building a more solar panels that we don't use in summer.

Of course once we have solar that we won't use in summer there will be programs to use that power. I suspect things like ore refining, steel mills, and the like: will start running in summer only. They will go offline in winter for maintenance. (Investors will make a ton of money buying in summer and selling in winter - as they already do for lots of other commodities that have seasonal aspects)