Some sort of battery based tech that is fairly unconstrained by site requirements, as well as complex construction engineering requirements seems to have much more potential.
The Bath County Pumped Hydro plant can give 3GW of power with over 10-hours of storage. That's 30GW-hrs. How many lithium ion batteries do you need to compare against that? "Small" Pumped Hydro Plants are hundreds of MW-hrs, and large ones are dozens of GW-hrs.
CAES in Texas was constructed inside of abandoned mine-shafts. Line the mine-shafts with steel to contain compressed air, and bam, cheap energy storage.
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The USA has lots of lakes and mineshafts. And electrical storage in one area can serve multiple states. Indeed, the Bath County Pumped Hydro plant contributes to the electrical stability of 16 or so states.
A $5 billion project here and there will serve more people and in a wider area. If the USA can take advantage of natural resources, in a sustainable way (it doesn't seem like Bath County's Reservoir is damaging the environment), then it should happen. We know how to make hydro-plants that are safe for Salmon and other wildlife (we need to ensure that future Hydro plants need salmon ladders for example), but as long as environmental concerns are identified and addressed, leveraging our natural resources is the most obvious way forward.
I didn't intend to discount the projects you mentioned, there are lots of approaches being pursued. The more of them get a real crack at the market the better in my opinion.
See CAES storage (Texas) and Pumped Hydro energy storage (https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta...)