I was just thinking again about this.
I was volunteering in a shelter -where we took on more damaged dogs and did lots of training with them. One dog I worked with in particular, a GSD who had guarded her whole life-and had a lot of issues-had NO idea what to do with a toy, and no interest in them at all (interest was thoroughly in circling and yelling).
With lots of time, cooing and pretending to have interest in the frisbee-I had her fetching the frisbee happily (once it landed-not in the air) in several weeks. So I think it could be done!