The 2 options are not quite the same, so I can't see anything like this existing.
When you use
New Folder with Selection (4 items) (for example) creation of the folder is a simple task, to create a new folder and request a name for it.
But once a folder is created, there are multiple results from a proposed "unwrap" command, depending on if you select all the files in the folder or not. Let's say you select all the visible files with the mouse instead of cmd+a, but you miss one that's scrolled off the bottom:
- Should it abandon the attempt to unwrap, because there are unselected files?
- Should it move the selected files back, and leave the orphan file alone?
- Should it move the selected files back a level, and then remove the folder regardless of the fact that it still has contents?
- What if there are further subfolders?
- What if files don't have permission at the next level back, say they were on the users home directory, or the root of the filesystem?
The choices in copying stuff back one level and removing their previous location is far far tricker than simply creating a new folder and moving the selected files inside.
I'm sure that custom scripts can be written to provide something similar, but I imagine the use case it pretty unusual, as well as much trickier to implement in a way that won't confuse, as such it doesn't exist by default.