When should teachers be held responsible?

I am SUPER frustrated today. I have a student that I have been mentoring...basically all up in his biz-nas! He's a great kid but has not had any boundaries established either at home or here at school. His teachers from last year are know for not having the great classroom management skills and he ran any class he was a part of. That was before he met me! We became "friends" last year and I requested to have him in my class this year. Since most teachers don't request the more challenging kids, no one put up a fight...so I won him! He has once again become my friend this year! He's been working so well in my class (a completely different kid than the one I observed last year) and actually leading great math conversations at his table! He's blown away anyone who has seen him and has "known" him. He has been spending his lunches with me, some by his choice others not. Bottom-line, I've been working so hard on developing a good relationship with him and it has paid off!
Today he walked in my class and said he needed his stuff. I asked were he was going and he told me he couldn't go to school here anymore because his family moved and they wouldn't let him open enroll. They won't let him open enroll here because of his poor behavior last year. But I ask you, how can he be blamed? He just did what his teachers allowed! He lived up to the expectations they set for him...which were obviously low!
When will teachers be held responsible for failing our students? I can't believe that this situation is unique to my school. All accross America, teachers put the fault to the students for not learning. But could you learn from someone that hated you...or expected nothing of you? I admit, I had some crappy teachers in my time. But my parents and the expectations they had for me is what kept me on the straight and narrow...mostly ;) What about students whose parents don't seem to care. Even if their parent doesn't care...we should! If we don't teach these kids now...no one will...then we will pay for them to live in jail in 5-10years. I don't know about you but I'd rather have my $$$ going to schools instead of prisons.
So I ask again, to whoever is out there in cyber-world, when should teachers be held responsible for failing at their job...teaching ALL students?