IIRC, there were two traits that don't seem to change over the course of one's life: gregariousness, and level of anxiety.

Traits other than those two can change. Classic example: an alcoholic who becomes sober.

An alcoholic that becomes sober is still an alcoholic, they are just in control over their alcoholism.

A rude person that becomes conscious of the way it comes across to act disrespectfully may still be an rude inside, but if he/she is in control of the disrespectful behavior then I count that as real change.

This kind of relativism is what it's all about. The ends don't justify the means because the ends are part of the means. But here we don't have that problem because to us only the end is visible. Or, the issue here is that you think the change is pretend where another considers it part of completion of a full change.

It's not pretend change, there is actual change in the behavior. That is something real.

I'm a different person than I was ten years ago. Some things remained the same, a few things changed.

It's hard to quantify how "different of a person" you are. But if there's one thing reading psych literature taught me it's that traits like aggression and compassion (or lack thereof) are measurable and shockingly persistent in people over decades.

Circumstances, triggers, and incentives change wildly. The world is in flux. But people's attitudes generally are not.

There's a huge difference between "can't" and "don't." People can change.

I have a degree in psychology and I would love to know which studies you are referring to there because I am not aware of such well established facts.