I thought it was interesting that the publisher blames its demise on conditions in the United States. Usually magazines fail because the editors and publishers fail to provide the content that their audience wants but here we seem to have a magazine that fails because the audience wasn't buying what they were selling.
I think as a general rule, high quality material properly targeted, will usually succeed. Once you start missing the target, then things tend to spiral down the slippery slope.
But when all is said and done, Glamour is a difficult target, and only a very limited number of publications will consistently hit it (since its a moving target).
All the pieces must be in place for Glamour to work.