People have more disposible income now based on how much is spent on yearly smart phone updates, Kindle, tablets, etc. The question is moreso whether those people are interested in a gaming system. They already have devices and services that do everything, Comcast Triple Play etc.
Gaming is dominated by young men with money to waste, and I'd imagine many will jump on board the next gen; especially as their friends start playing next gen CoD more than the 360 version. To me personally $500 is money I could think of better things to spend on, like upgrading my PC. But I know plenty of guys who started saving for the next Xbox last year; from guys with good jobs in finance to cashiers to unemployed students. Ironically they all now plan in getting a PS4 instead haha, but perhaps MS' clarification on "always online" will bring them back.