I kinda get what you're saying, Hannah did fail at saving herself (which I think she admitted) in several ways, but I don't think the cause of her death is simple at all.
The tape subjects, I think, were showing us how they damaged her mentally, emotionally, and physically.
With her parents, all parents make mistakes and aren't perfect, and they raised a happy and healthy daughter for 17 years until she killed herself. Yes they also may have missed signs, but Hannah didn't go to either of them for help.
Now taking Hannah's mental state through the first season into consideration, her depression was terrible that she felt the only solution was suicide. A person like that is no longer in a rational state of mind, at that point she wasn't the healthy and sane Hannah we saw before.