My experience was unique in that I was in and out of mainstream and deaf schools through my K-12 setting, and the school system I was in did serve many deaf and hard of hearing students. What happened was many students were in special ed classes for the subjects they were weak in, we had study halls until we were deemed able to be 100% mainstreamed, and a deaf ed teacher was in charge of my IEP and communicating that to the teachers. My education was very successful in that regard.
Yet, I can remember the year I got D's in physics because the teacher wouldn't assign us readable textbooks, had chaotic handout systems, didn't write down information and was never clear about what he was talking about. Nothing made sense and if I asked him anything I never got an useful answer. In fact, he was rude and belitting to me in class for asking questions about what "he had already discussed." I had not been belittled by a teacher before for wanting to learn, and it was depressing.
I read in the comments that many interpreters feel concerned about accessibility in community college. As I've gone from Gallaudet to mainstreamed colleges, I can say it's not just community colleges. I've had horrendous interpreting problems-- and I've also had faculty try to blame me for being too hard to work with simply because I asked for some organization and not to have people talk over each other or interrupt so I could follow the conversations.
They're right. Interpreters alone don't ensure accessibility in education. The faculty has to be educated, willing to work with students out of class, and in some cases, held liable for discriminatory behaviors such as talking to the blackboard (impeding oral students from lipreading them clearly), giving oral quizzes which deaf students can't write down and listen to at the same time, talking too fast over relevant information and never writing down homework assignments.
At the K-12 level, social development matters, including helping deaf students to meet their classmates-- even arranging desks in pods so they can face their classmates for team work would help; that was done in one classroom I was in. Also, there must be deaf schools available. What happens in programs with large numbers of deaf students is that the school runs a deaf school within the school-- a teacher hired to work with the deaf, interpreting, and so forth. But the administration has no way to ensure quality of education and they may not care and look for the best way to slash costs.
If this sounds complex, it is. In most cases, people who understand and care fight an uphill battle against people who don't understand and are paid to do other things they consider more important than ensuring educational success for a deaf student (and this means basic things like language development and literacy.) In effort, they must reinvent the wheel because there is no deaf school set-up.
Deaf people can succeed as well as anybody else, but nobody can succeed if the support system is not there-- parents, family, friends, at least one sympathetic teacher, interpreters, role moels, people with kindred experience, etc.