I wouldn't really disagree with any of that. The public has long believed that psychology isn't a science even though it's long been based in the scientific method which is the definition of a science. Does that mean there aren't biases, trends, whacks, etc? No. Once upon a time, homosexuality was listed in the DSM. But there are biases, trends, whacks in any field. If there wasn't a successful surgery for a medical condition, I doubt people would declare that the medical profession was therefor illegitimate.
Of course money is a driving factor behind psychology as well, just as it is any profession.
As for the successful treatment of the mentally ill, I think the public looks at the severely mentally ill and because they don't act normal consider them unsuccessfully treated. But to a psychologist or the person themselves, successful treatment could simply be a measurable increase in their level of independence, even if that increase doesn't make them "normal" or as functional a member of society as the typical person.