Without the climate crisis, doing this R&D only once the technology becomes required and therefore economically feasible would be fine. But with the current decarbonization targets, you cannot just build renewables until you hit a threshold, and only then start testing out storage methods while putting the green energy infrastructure industry into hibernation for 20 years. We pretty much need to do everything, right now, at the same time.
This is also why there is a big economic advantage of hydrogen storage. Decarbonizing steel and ammonia production with blue hydrogen (i.e. electrolysis using electricity created with the current fossil fuel heavy generation mix) is already a big potential market which is already kind of feasible, reducing the need for government subsidies to get the tech off the ground.
Once the R&D, production and sales pipelines for blue hydrogen are up-and-running, you just scale up with increasingly mature technology. Then transition the energy input from carbon-intensive to carbon-neutral. This should happen automatically, as green electricity is the cheapest form of energy, and the hydrogen production acts as an energy-sink for any surplus production, mitigating those adverse market pressures acting on renewables after you reach a certain percentage threshold on renewable energy generation. Only then you eventually ramp up the use as energy storage via normal market mechanisms.
Unfortunately the media always seems to put the cart before the horse. Energy storage is not the first step, but should be the last.