I think the core of your idea would work well in theory; a much simpler example would be heating water, which both residential and commercial buildings do quite a lot. Once you have hot water, you can keep hold of it for quite a long time in a properly insulated tank.

Or at a higher level of abstraction, instead of us trying to figure out which "energy dense step" is the right one to target, instead the grid can provide a real-time price signal that flexible loads can use to get a cheaper overall rate by selectively turning on when the demand is lower.

This stuff is pretty well discussed under the umbrella of "smart grid" technologies: https://en.wikipedia.org/wiki/Smart_grid#Market-enabling