There are two standard disk locations. Program distributed components and user components.
For SketchUp 2018:
The component libraries (folders) distributed with SketchUp (and used by any user account on the machine,) are located …
%ProgramData% resolves to:
"/Library/Application Support/SketchUp 2018/SketchUp/Components"
This is in the HD Library path.
The user component libraries (folders) that are automatically enumerated (when SketchUp starts) and listed in the Components inspector panel are located …
%AppData% resolves to
"~/Library/Application Support/SketchUp 2018/SketchUp/Components"
"~" resolves to
"/Users/<USER>" aka the user’s HOME folder path.
Well, obviously if the folder is empty, then you (the user) have not saved any user generated components in that folder.
As said above, SketchUp (like most applications,) store user specific resources and non-user specific resources in separate disk locations. (It always has been thus generally for software. Although in earlier Windows editions of SketchUp this rule was violated.)
The path that this preference is set to upon installation is the user components library path (as given above, and in the SketchUp application release notes for 2017. See the subsection labeled “Standardized Product Content Locations”.)
This also applies to folders for Classifications, Gems, Materials, Styles, Templates, and Plugins.
Beware, that you can change this path so that the Save As … dialogs open to another disk location. (You might do this if you are going to be working on a special library and you want the dialog to open directly in that subfolder, or you may be building a special library that is outside the SketchUp versioned user library and want it’s path to open in the Save As… dialog.)
However, changing this path preference does not affect the location where SketchUp looks and enumerates user component folders at startup. It only affects where the Save As… dialog opens. (So changing the path should likely only be a temporary workflow.)
Have you tested the utility I posted yet ?