Yes, it comes down to the fact that IndyCars' oval races have not been well attended in recent years. The consensus among fans is that there isn't much action on event days outside the main event. This is why the Silver Crown cars were added at Phoenix this weekend.

The tide seems to be shifting however: with the downturn in NASCAR's popularity, in both attendance and Tv numbers, IndyCar is looking more and more attractive to promoters and sponsors. Gateway was added to the schedule this season for an August date, and word on the street says that Kentucky Speedway recently approached the series about getting back on the schedule in order to replace their recently lost stand-alone Xfinity date.

The answer to the question is if you love Indy-style oval racing (like me), watch them on Tv, and go to one (or more!) of the races near you. Also, maybe send Kentucky Speedway an email and let them know that you'd love to see IndyCar back; I know I plan to.