The comparison is unfair. Drag and drop has long been built into the Windows API. I believe that the SketchUp Installer for Windows registers several drag-and-drop file handlers for SketchUp associated file extensions. (ie, SKP, SKB, SKM, etc.) Also standard image files of various extensions can be drag-and-dropped into SketchUp.
The Ruby code here …
wd = UI::WebDialog.new('Drag and Drop',true,'test',800,600,100,200,true)
#>> #<UI::WebDialog:0x0000000ab98f98>
wd.set_url('file:///C:/Users/Dan/Documents/SketchUp/SketchUp 2015/Models')
wd.show
… produces the following nice scrollable / sortable (by clicking column headers) / sizable (by dragging column header margins), etc. (No Javascript / No framework needed. MSIE knows how to display FTP directories, and it does not care if they are local directories.)
I can grab any of the SKP items and drop them into the model. Also can grab the PNG image and drop that into SketchUp as an image component.
(I can also do normal things we can do in the normal file explorer window, such as rename files, delete them, etc. “Open With…” via the right-click menu. Etc.)
EDIT:
Actually SketchUp drag and drop handler is smart enough not to allow us to drop the last autosave of a file into itself. (But it allows dropping all the previous autosaves.)