Other than that, I rather enjoyed the story. Though, if you try to take it as a fable, you run into some trouble - the end moral seems to be "be happy with your lot in life and don't aspire to be more than you are". Oy vey.
I didn't take that message from it, though I guess one could.
To me, it was more what the Rabbi said explicitly at the end: if you keep looking far afield, or in books, or to shortcuts (or, to extend the analogy to modern life, on TV or the lives of celebrities) for happiness, you'll miss the happiness and satisfaction inherent in your life as it is now, warts and all, and that you can make it by focusing on it. It's more "Don't try to take the easy road; there isn't one." It may also be, "Go with your strengths."
Also, it seems to me that Avram could still become a wonder worker. He just wasn't going to do it by reading about the wonders of others.
In a world where wonders
can be worked, but is otherwise much like ours (presumably), I suspect that Avram could, by applying himself to his farm, really
seeing it and all that God gave him in it, could become a 'farm wonder' worker and eventually be renowned years hence as "Rabbi Avram, who could grow enough to feed a city even in the worst drought," or some such thing.
However, by the time he's able to do such things, it no longer seems like a wonder to him any more, because he
understands how it all works and it's just something he can do, much like Avram's rescuer casually freed the birds.
And even if he does see how it's wondrous to others, he knows he's channelling the power of God and has come to understand - internally, deeply, not just intellectually - that whatever he does himself, it's still small potatoes (har!) next to the wonder that is God and his creation.
[Note: it bears repeating that these ideas do not represent my view of the world in which we live, but are about the fictional world of this story, though the 'moral' may well apply here as there.]