For the future, EVs also help, but are not required - insofar as they're mainly nighttime loads, steady draws, and easy targets for charge rate modulation (or even reversal). Nobody cares exactly when their vehicle takes power from the wall, so long as it has a full charge when they told it to be done by. The more flexible they let their car be, the cheaper they get their power for. But again, this sort of arrangement being wirespread is not a requirement - just a bonus.
I've also wondered if the whole smart device thing could end up being a net bonus -- for example, during the cheap hours, freezers/electric water heaters/dishwashers/etc. could do their thing. Most of this could of course be done with a simple timer, but having some amount of communication with the grid and the personal schedule of the user could be more effective.