I had a stay in a rehab facility for 3 months after having severe psychiatric issues, and there i met a bunch of borderliners who were also on rehabilitation there. They really don't have it easy, but it was good to see how much they improved when getting adequate care. As you say, as with any severe psychiatric disorders, the patient has to want to get better, which includes even realizing that something is wrong.
These things are the largest barriers for successful treatment in many psychiatric conditions, e.g. paranoid schizophrenia which suffers from abysmal compliance rates, often leading to a cycle of "on meds -> feeling well, but the meds have side effects -> dropping the meds to get rid of the side effects -> back to the start, but with the idea that the doctors want to poison me".