This is 80% a very good point; for the other 20%, I think sometimes about how experts in my field will still disagree, vehemently, about stuff in the field, and seemingly show all the same biases -- they're defending territory, they're viciously contesting for status, vs trying to get closer to "the truth" through the scientific method.
No one is immune, so whatever wisdom the OP gains on this quest will still be useful even if s/he attains the ultimate height of expertise on whatever topic.
Yeah, expert disagreement does occur (we can see it in real time on HN itself) and often it boils down to "I don't want to do more work" or "that is better but the cost/benefit isn't there".
But even then it's better than uninformed arm-chair quarterbacking. And for those watching from the sidelines, if you watch long enough, you start to get a "feel" for the various sides.
I suppose it at least narrows the points of disagreement? So that, e.g., economists will agree on a _lot_ of stuff, even though their points of contention are so magnified that it appears they agree on nothing?
The HN example is interesting. The one topic that comes up consistently on HN that I feel like I have expert-level knowledge of (bitcoin) reveals mostly tribalism / religion couched as rational discussion. It was the most visceral illustration for me of that construct (can't remember the term) about how you read about some topic in the newspaper where you have expertise and say to yourself: this is such crap, they've missed all the nuance. And then you go on to other parts of the newspaper and believe it un-critically.
No one is immune, so whatever wisdom the OP gains on this quest will still be useful even if s/he attains the ultimate height of expertise on whatever topic.