"Others" do NOT think exposure is NOT important. "Others" have a right to think it, but NO ONE thinks that. Everyone thinks exposure is important. This is a classic straw man argument. You pose a fallacious argument that no one made, then show how it is wrong.

I didn't read your long post, couldn't get past the opening statement. Now, the question was "how important is exposure." That implies to what degree of importance, a comparative value perhaps. Of course exposure is important, that question did not imply it wasn't important at all.

My opinion is pictures taken with the lens cap on are doomed to failure. "Others" have a right to disagree. I could go on with details on my opinion on taking pictures with the lens cap on, but I think you get the drift.

However, exposure is not as important as say, focus. Another take on the question as posed might be how far off could exposure be and still be fixed.