As a long time, low volume contributor, I see 2 explanations for what happens:
1. There is not a lot to contribute as a lot of matters are already covered. This is not a bad thing at all.
2. Moderators do a very bad job. Last year I created an entire article about a popular vehicle, it took 6 months to be published and it was just about a page long with solid references. At one time it was rejected because it had "not enough external links", so I added half a dozen links to the dealers selling that vehicle, on top of the original manufacturer page. This discourages contributors and it is a serios problem.
Comments
As a long time, low volume contributor, I see 2 explanations for what happens:
1. There is not a lot to contribute as a lot of matters are already covered. This is not a bad thing at all.
2. Moderators do a very bad job. Last year I created an entire article about a popular vehicle, it took 6 months to be published and it was just about a page long with solid references. At one time it was rejected because it had "not enough external links", so I added half a dozen links to the dealers selling that vehicle, on top of the original manufacturer page. This discourages contributors and it is a serios problem.