My question is WHEN will you introduce a possibility to transfer DNG files via Google Drive, Dropbox or any other cloud service apart from CC (or via cable). Now, that wouldn't be a problem but a CC syncing speed is painfully slow (my internet speed is fine). Uploading to faster and more reliable cloud serviced would solve that issue.
The two links in your post aren't completely up to date. If you're using iOS, an Export Original option was added in version 2.7 in May. It does export a DNG raw to the iOS Camera Roll, but unfortunately you can only export the currently viewed image, not multiple images.
It was covered here, in the section "Other features in these releases":
Export Original, enabling you to export the original files, including DNGs captured in the camera as well as raw files imported through Lightroom Mobile and Lightroom web (Lightroom Desktop does not upload originals to the server)...
What happens from there seems to depend on the sync service being used. When I sent the exported DNG from the Camera Roll to my Mac through iCloud Drive or Box, it worked great, I picked up the DNG on my computer and could open it with any application that can view a DNG. But when I sent it through Dropbox I only got a JPEG on my computer for some reason.