Ah, yes, the convenional wisdom that young is king. It amazes me that businesses are so eager to target the poorest, most indebted, and rapidly declining demographic in America, especially in advertising. Yes, I'm in that demo, but believe me, I am in no way representative of it!
My sense of that demographic is that in flush times they are quick to spend, fast and freely - after all they're single and free - but in lean times they spend little or none at all because they tend to be the quickest to be let go and - thanks to their free-spending ways - have little in the way of savings to tide them over the lean times.
So, not only did JCP commit the cardinal sins of (a) rudely dumping your bread-and-butter customers and (b) trying to belatedly jump into an already over-crowded market, they also did so right at the point where their newly-targeted demographic had pulled its spending-horns in.
I.e., dumb, dumb, and dumb.