It's a market share problem, media footprint problem, growth problem, or however you want to characterize it.
As I posted yesterday:
Population growth from 1970 to 2010 (in millions)
PA 11.8 to 12.7 (+7.6%)
MI 8.9 to 9.9 (+11.2%)
OH 10.7 to 11.5 (+7.5%)
VA 4.6 to 8.0 (+73.9%)
NC 5.0 to 9.5 (+90.0%
GA 4.6 to 9.7 (+110.9%)
In 1970, PA, OH, and MI were the 3rd, 6th, and 7th most populous states. Currently, they're 6th, 7th, and 9th. It's not hard to envision all being out of the top 10 by 2030.
EDIT: Here's a link to current population growth rates. The highest ranked Big 10 state is Nebraska at 25, which is of little value considering how small they are. VA, NC, and GA are large states that are still growing.