Well, Ken, since I mention your name in my post, you are in on this too! 😀
Actually, the reason why I mention your name is that I thought I recalled you running into this issue, either yourself or as you were helping others.
This "space" problem has been around forever, both due to the required server size, and due to the cost. I even remember Bob Puffer, from Luther, giving a presentation at a Moodlemoot nearly 7 years ago about how he was developing an API, or something like that, so that GoogleDocs could be seamlessly integrated into Moodle.
seems to have two problems: 1) getting rid of what is already on the server, and 2) preventing an over-capacity situation from occurring again.
For 1, I know that we get questions like this, often when big videos have been uploaded, about how to go into the moodledata folder and remove the big video. I don't pay attention to possible solutions because I am careful not to do this on my Moodle.
For 2, one can use some of the "upload" Moodle restriction settings, buy more server space, or use your suggestion to try to use some of the "free" storage solutions.
(I will fix that "rating" issue in just a moment. 😍 Your help is always appreciated, Ken.)