Well if anything the Raspberry Pi isn't particularly short of online teaching resources, five seconds with Google will tell you that.
The Pi foundation has projects and there are third party projects, but should teachers expect absolutely everything on a plate? Should test tube suppliers come up with a chemistry course, sports kit suppliers come up with a PE programme, or dictionary publishers come up with an English course?
No, so why should IT be any different or self-explanatory?
If teachers who teach IT are only regurgitating stuff they learned from 10 years ago with different hardware or if kids think six copy-pasted lines are programming then there's obviously something wrong, but it's not with the Pi. Next you'll be blaming Bunsen burners for bad science results.
And the fact that your Pi is gathering dust in the attic is not really the Pi's fault either, it's only doing what you've decided to do with it.