Question: Who do you think is paying these "negative prices". Spoiler: It's the TSOs. They can't do that for long, or simply go bankrupt.

Yes, "storage of the abundant renewable power" is a key piece of the puzzle, but "The power available on the grid must always equal the power consumed" is something that can not be broken. If it does, equipment will break, people will be without power, and it'll cost the TSO tons of money to repair.

There's post scarcity, but only during a short time of the day, when power consumption is relatively lower (it spikes when people come home, because everyone turns their lights and machines on around the same time).

Oh, and I don't know about the USA, but the Dutch grid is pretty much overloaded, so there is no space to move the power to the storage units (whether the storage exists or not doesn't matter ATM). We're working on it, but here's we're kinda fucked ATM.