As far as general advice on helping your kid to get into reading, I think this question/answer does a great job of giving pointers. But your question goes to a different topic - how to deal with your perceived failure in teaching your child to read.
I do not want you to think that I believe you have failed your child. In spite of your own words to that effect, the rest of us in this forum do not know enough to know whether this is fact or perception, but really, we do not need to know.
All of us have areas in which we feel, rightly or not, that we have failed. There are areas where I feel I have failed my children. I am a person of faith, and yet I have failed to teach my children my faith as I should have. My wife and I have also failed to model a husband-wife relationship that is full of grace, patience and kindness. Still my kids have managed to grow, so far, into delightful, responsible teen agers (and one pre-teen).
I guess my advice to you is to keep trying, persevere. You may never teach your child to love reading, but you will only really have failed, if you give up. I suspect surrender is not an option for you, and that is an excellent thing. There is one area which I consider the biggest area of failure in my life (too personal to share here). I do not know if I will ever have total victory in it, but I have determined that if I should not succeed, I will certainly die trying. There is contentment in that, as well as encouragement to keep at it.
I would also encourage you to be open with your son. Take him out for a soda and show him his scores. Speak to him about your own sense that you have failed him and how much you wish you could teach him to love reading. Encourage him to persevere and tell him that you also will try to persevere with him. Speak to him as if the two of you are in this together, because you are. But also express your belief in him and his ability. Tell him and make him believe that you know he is capable - not as an indictment, but as showing confidence in who he is.
At the same time, I am not advocating blind belief. Not doing homework or not putting effort into something he needs to do is simply not acceptable. But these test results are not the time to deal with that. The time is the next time he comes home from school - know what homework he was assigned (find out any way you can - asking him or emailing his teachers), and sit on him until you know he has done it and done a good job on it. Get him to bring home all his books and notebooks and anything else school related, and go through it with him every day until he gets in a pattern of coming home and doing his homework. Sit with him and look through them and ask him to tell you about what happens and what he is learning in each class. Be as positive as you possibly can, but do not take "no" for an answer. Gentle and encouraging, but firm as a rock.
As for reading itself, one small suggestion along the lines of what is on that answer - pick an easy, fun, read that gets you hooked from page 1, something like Andrew Clementz "Things Not Seen", and read it with him - take turns at reading outloud. You are the boss, so don't let him think this is an optional activity.
Like Winston Churchill said (and got a 10 min standing ovation for saying it) "NEVER SURRENDER." And I will be praying for you and your son.