I was the one who raised the 1812 example in the context of
Wikipedia's coverage of military history; see Richard Jensen,
"Military History on the Electronic Frontier: Wikipedia Fights the
War of 1812," ''The Journal of Military History'' 76#4 (October
2012): 523-556; the page proofs (with some typos) are online at
http://www.americanhistoryprojects.com/downloads/JMH1812.PDF
My argument is that Wikipedia is written by and for the benefit of a
few thousand editors -- what the readers or the general public wants
or thinks or uses is largely irrelevant.
The growth then depends on the need to recruit new editors --
using the details from the 1812 article I suggest that fewer and
fewer new editors are actually interested. (I also looked at other
major articles on WWI, WWII, the American Civil War & others and
found the same pattern.)
Look at it demographically: apart from teenage boys coming of age,
the population of computer-literate people who are ignorant of
Wikipedia is very small indeed in 2012. That was not true in 2005
when lots of editors joined up and did a lot of work on important articles.
So I think that military history at Wikipedia is pretty well
saturated. That does not mean there are not more possible topics (we
have about 130,000 articles (including stubs) now and major libraries
will own maybe 100,000+ full length books on military topics). I
suggest that new editors need to have an attractive new niche that is
not now well covered. I suggest that they will have a very hard time
finding such a niche that allows for the excitement of new writing
about important topics. (such as took place in back in
2005-2007). Personally I greatly enjoyed writing about George
Washington and Ulysses Grant and Napoleon--that's why I'm here. I
would have trouble explaining to someone why they should write up
general #1001, #1002, #1103 ... let alone colonel #10,001, 10,002, 10,003 ....
Richard Jensen
User:Rjensen email rjensen(a)uic.edu