That's exactly what killed my one and only attempt to substantially improve an article (not just typo-fixing and stuff):
The two guys with a lot of edits on that page couldn't stand someone else editing "their" article.
Sure, they tried to bring up superficial disagreements about the content, but that could have been resolved trivially. It was very obvious that they didn't want someone else on their lawn.
Unless Wikipedia fixes exactly that ownership problem, specifically, I doubt they can improve their attraction and retention rate of contributors.
And that is a social problem. I bet it will never be fixed.