I think you're right that that was their expectation/intention. I think it failed because experts don't just randomly go through old questions and make modifications. What prompts knowledgeable people to share their knowledge is new questions asked by new people.

I think the problem is that the creators, and by extension the moderators were bought into the idea of a giant wiki of all programming knowledge. The vast majority of the users just wanted a Q&A site. This led to the infighting and lots of counter intuitive rules as the gamification part conflicted with the goals of being a wiki.

That approach was untenable because then it still attributed the answer to the original author, even when the content was updated. That could cause real-world issues. “Hey, why did you say that Python is untyped on SO? I thought you knew something about it.” “I never said any such thing.” “Here’s your answer where you say it!” “WTF.” And sure enough, there’s some dumb answer with crappy grammar and mistakes, still attributed to you.

That was a terrible, awful plan, and I always reverted edits to my answers that went beyond fixing typos or updating old links.