Well a few things to consider... success is relative. One expects a rich wealthy person to have kids who will go to yale and become lawyers and eventually judges. That is success in that world, because it can easily be obtained when you have money and the right connections.
For someone who has a mental issue, maintaining a regular job and being independent is a success because it takes so much effort to be act like a normal guy/gal. Success should be measured not in how much you achieve but in what you went through to get there, imho.
As for people with psychiatric diagnoses... Speaking from personal experience, I alaways have people tell me I am not reaching my potential. I should be doing more with my life. I am very intelligent, capable, likeable, and could do soo much more with my life.
Then they find out I have a diagnosis, and they flee. They don't really want me to be in a workplace with them. They don't want me to be around them, then they blame me for not melding into a society that does not want me

So I think in the case of people with mental issues, victim blaming makes society feel better about itself at large. If it is our fault, it is not their fault, after they try to encourage us by telling us about our potential, etc... so we bring the giref on oursevles and the peopel who are scared of us are absolved.
Do you really think it is weakness that yields to temptation? I tell you that there are terrible temptations which it requires strength, strength and courage to yield to.