But storage has dropped in cost over the last 10 years, by a factor of around 5x.

And with cell chemistry that is more resilient to charge and discharge cycles (LFP) coming to fruition in the last 5 years (and at a lower cost than NMC) it makes sense that we're only now seeing large-scale investment - the yield curve has hit the sweet spot.

I don’t know, apparently Tesla’s battery deployment in Australia paid for itself really quickly as one possible counter-example.