You Sir, are correct. The only time I ever hear about "security through obscurity" is when it fails, not when it succeeds. I got so used to the open source model where everything is known and flaws are more likely to be fixed. I guess that doesn't work for every application.
I have to say I almost came to write the same thing, and then the above comment got me thinking. I guess buried treasure is amongst the most successful usually... In that it keeps it away from those the owner was hiding it from for many decades or more, before accidentally getting 'cracked': http://www.telegraph.co.uk/news/worldnews/northamerica/usa/1...