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.
The problem is more about regulatory capture. An industry adapts to a regulation, and creates winners and losers. Once the regulation no longer makes sense (costs taxpayers/consumers more than it benefits), those who are winning from it have a strong interest in keeping it around anyway.
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.
Agreed. And, IMO, the fix to regulatory capture isn't adding a mechanism to directly make deregulation easier. Instead, it's to (somehow) remove the money from politics/campaigning.
You can argue that is not effective enough perhaps, but the mechanism itself exists.