The solution is to cut off industrial and commercial sites first, which draw the most power anyways, and keep residential zoning online as much as possible. The economy can take a break for one day.
Some industrial customers like datacenters have strict availability agreements with customers and won't be able to accept prolonged cutoffs.
Forcing non residential customers like these to curtail their use would likely end up driving the industry (and corresponding tax revenue) elsewhere.
But what you're talking about does already exist, and it's called demand response, https://www.energy.gov/oe/activities/technology-development/...
But that's not the way our legal and political system actually works.
Edit: I’ve interpreted the second part of your comment as an objection to the first part, but if that wasn’t the intended message it’s my bad :)
I'm suggesting that what I think ought to be the way the world works in fact is not the way it actually works.
This is a criticism of our current system, not using it as a reason to dismiss the idea of changing it to something better.
Unless it's already built, it's rather expensive to rebuild.