An agency can remove a regulation it created. Congress (via the linked law) can also remove a regulation. Congress can also create regulations via legislation (though they typically don't go to that level of detail).
And we have to remember, at one point, every regulation that exists was created to solve a problem / prevent a harm. The cost of removing that regulation prematurely is reintroducing that problem / harm.
A good example is the state franchise laws against car manufacturers owning dealerships. Why can't Toyota sell me a car directly? Direct manufacturer sales seem to work fine in other contexts (e.g. Ikea). In Europe they're moving more and more direct sales. There's no good reason to keep them here in the US, but the dealership owners who benefit from these laws are the only people impacted directly enough to bother hiring lobbyists.
It would be comforting to believe so, but that requires ignoring every aspect of human nature.