I was an old-timer on Wikipedia who began contributing in 2002.
I've witnessed layers and layers of bureaucracy be added to Wikipedia all under the benevolent dictatorship of Jimbo. I've witnessed what used to be a culture where all editors were considered equal become one where there are definite castes and hierarchies (and cabals).
It just isn't worth the effort to edit anymore.
Case in point: from 2002 to 2006 I was one of the primary editors of a set of articles that had to do with a subject that definitely has politics surrounding it. All the editors involved and I did our best to present both sides of the topic and to try to keep the articles fair and balanced. The number of editors was sparse and it was relatively easy to keep the articles on track.
A couple of years ago a new user started editing these articles. He was extremely contentious but a skilled at wikilawyering. Every edit he didn't agree with would be dragged by him down a rathole of WP:V, WP:NOR, WP:POV, WP:PSTS, and so and and so on ad infinitum. It doesn't matter how well *your* edits are sourced from quality peer-reviewed sources. If he didn't agree with your edits he would find something to complain about; the journal you are citing isn't respected enough, the author you are quoting has an obvious bias, your summary of the published literature doesn't agree with how he would summarize the published literature, etc, etc, etc. Similarly, any objection you had to his edits (or to the overall effect his edits in aggregate were having on the article) would also be dragged down a similar path of his gaming the system.
Editing the articles involved simply became too painful to continue. If you wanted to make any change that this user would disagree with then you had to prepare yourself of days of arguing with him before he would leave you alone. Similarly, one became hesitant to "correct" any of his articles because of the time-sink that you knew arguing with him was going to become.
The existing editors tried many times to work within the system to make this user stop. There were multiple attempts at mediation and arbitration. But over time all of the "old" editors simply gave up. It just wasn't worth the effort anymore.
When I visit these articles today I am ashamed at what they have become. What was once a fair attempt to present all sides of an issue has become extremely one-sided and quite misleading to a reader not familiar with the subject. The "problem user" has become in effect the only editor of these articles, tolerating only a handful of other editors who primarily make grammatical and punctuation changes.
The only hope for the articles in question is that this user eventually gets tired and quits. He has won in his attempt to take over these articles, everyone with an established interest has been driven away, and I don't think any new user is going to be able to mount a challenge as he will simply tie them down in wikilawyering forever.