Many billions of dollars are today going into constructing factories worldwide to produce equipment for storage of numerous kinds. It takes time to build the factories, and then time to run them to build out the storage capacity.
There is, thus far, little use for storage, because there is not enough renewable generating capacity yet to charge up storage. (Charging it by burning fossil fuels would be stupid.) By the time we need much of it, it will be very, very cheap. In the meantime, building generating capacity and factories is the right use of capital.
Although people insisting there is a problem love to talk about expense of batteries, only a tiny fraction of utility-scale storage will ever be batteries. The cheapest storage is gravity, exemplified by pumped hydro, which represents today almost all utility storage. But there are many variations that all work.
The only uncertainty is which ones will be cheapest. Each is a different mix of build cost, maintenance cost, storage cost, charging cost, and discharging cost, with capex and opex for each. Different users will favor different places on those axes. Best for most uses are those that cost only capex, and store as much energy as you care to, cheaply.
Synthetic ammonia and hydrogen are attractive storage media, despite some higher costs, because they may be sold, and burned in gas turbines.
Liquifying nitrogen is extremely mature tech and, like the synthetic fuels, valuable in its own right. Power is extracted by boiling in ambient air to drive a turbine.
Compressing air underground, adiabatically, is another mature method. Compressing to a sea-floor bladder through a hose from a compressor onshore, likewise. Turbines, again.
Buoyancy, drawing a float down toward a pulley on the sea floor, using a winch onshore; and raising a very, very heavy weight up a disused mine shaft are other, very similar examples of gravity storage. Both have startup time of seconds, and are useful for stabilizing grids. Energy is released by running the winch out, driving a generator.
There are various battery chemistries, for cases where batteries are useful at all. All under consideration are much cheaper than lithium. Farthest along may be iron-air, molten-metal, and sodium-bromide, none of which are prone to fires.
Storage costs of all kinds are falling much faster than solar generating capacity. Utilities will build whatever is cheapest when they finally need any. As prices change, the mix will change. There is no value in picking just one, and plentiful value in using the right one for immediate circumstances.
Nobody needs very much storage, because you can always import and burn fuel. The cheapest fuel will be surplus ammonia and hydrogen, although burning aluminum powder for direct process heat has been used in production at local scales. Scrap aluminum is very cheap.