Of course, in reality it's often difficult to prove that a specific outcome was the result of a privacy invasion. It's not like insurers or employers are going to document that they discriminated unfairly, whether illegally or otherwise, in making their decisions. But we know all the things I mentioned can happen, partly because too many times there have been cases where real evidence was seen, and partly because in some cases incentives are aligned with poor behaviour and it's just plain naive to think it won't then happen if there's nothing to balance those incentives.
Privacy is important because it removes the ability to make those unfair decisions in the first place.
First off, let me clarify what I'm advocating for so we aren't talking past each other. I would like for the public to be less skeptical of organizations collecting large amounts of data, and storing it to analyze in aggregate for a variety of purposes. Particularly, if access to the data is controlled, and if it is only used in a sufficiently aggregated form. Society will reap tremendous benefits from enabling things like this.
I don't think of most of the cases you are describing as being related to this.