While annoying, it's not that big a deal. I mean, you chose to run Windows (or someone at your company did) which means "lean" or "efficient" were never really serious concerns from the get-go.
If you want a lean OS that's super efficient in terms of disk space you go with some form of Linux or a BSD. Windows would never even be a consideration (which is another reason why Linux market share on servers is so, so much larger than Windows).
A pretty decent 1TB SSD costs $60. That means 9GB costs about $0.54. It's even less if you use the old style, spinning rust disks.