the reality is this:
there are probably 30% of the season ticket holders who could be considered "casual fans"
They are fans of the Cardinals, but aren't hard cores. To them, selling their tickets for 3x face (effectively paying for a lion share of their playoff tickets) and watching it from home is a no-brainer.
I used to think it was about the demographics of the area and the fact that the team hadn't won.
Now I am not so sure -- I think its a reflection of the Phoenix collective attitude. We are much, much more laid back on life in general that those back east. I think it shows up in the depth of conviction (on average) of sports fan-dom. San Diego, Atlanta, Tampa all have had identical issues-- a mix of a transplant community and a laid back lifestyle.