Maybe it's the other way around sobay_terp.
One problem that the network carriers have is that the cost of transporting a passenger is based on the actual distance the planes have to fly.
Example: If WN flies PHX-BWI nonstop it's 1999 miles, CO will take you PHX-IAH-BWI at 2244 miles.
If fares and operating costs were the same (they ain't) who's got the advantage?