> Time and time again we see that 'one size fits all' is simply not true

Do we though? It feels like we're still in the stage where we're just trying to figure out what the best solution is for grid-scale storage, but once we do figure it out, the most efficient solution will win out over all the others. Yes, there may be some regional variation (e.g. TFA mentions how pumped hydro is great but only makes sense where geography supports it), but overall it feels like the world will eventually narrow things down to a very small number of solutions.