Dude, the system is so fucked and there's so little money in providing services for students struggling with things that they shouldn't have to that it's in no way the teacher's fault much of the time. I worked in a school last year, didn't teach, but was in a classroom with a teacher everyday and we had a student who was exactly the kind of kid you're talking about. Rarely came to school, and when he did he wouldn't do any work, would start fights, abuse classmates verbally, call the teacher a bitch (this was 4th grade), etc. We went through and filled out all the paper work to get this student a counselor and tutor to work with him one on one. Literally nothing ever came out of it. Didn't hear back for a few weeks, so we asked about it again, and were told it would take a few months to process and get something figured out. Nothing ever happened. There are so many more kids who need help than we have money, resources, and specialists devoted to trying to help them.
Yeah, there are teachers out there who don't take their job as seriously as they should, but it's really unfair to blame teachers for kids who need extra support not getting it, when the problem is often so much bigger than a lack of attentiveness/care from a teacher. When you're in a class with 25-30 kids, there's only so much time you can spend on just one student.