"what makes the difference between success and failure when trying to establish yourself in the design industry?".
* It was very different for me. there were very few illustratots in the late 1970s when I graduated. i got a job from the first publisher I visited!
I suppose it wasn't really an answer I was looking for based on what I have described above about Salisbury, but I suppose you could say from this response that possibly Luck can sometimes play a part. But more importantly as Salisbury stated in the time he graduated, there were very few Illustrators. And so, new illustrative talent was always needed. I have wrote in a post earlier referring to a article that the number of illustration graduates is by far more than the magazines and books and newspapers of today and so its not that your work isn't what agencies are looking for, yet most of them are always open for new talent, but instead that there are no jobs around. All you can do is promote yourself and remind people of your work, make them believe that you have what they are looking for to some extent.